A masticatory muscle whose action is closing the jaws.
Muscles arising in the zygomatic arch that close the jaw. Their nerve supply is masseteric from the mandibular division of the trigeminal nerve. (From Stedman, 25th ed)
A masticatory muscle whose action is closing the jaws; its posterior portion retracts the mandible.
The act and process of chewing and grinding food in the mouth.
The force applied by the masticatory muscles in dental occlusion.
Bony structure of the mouth that holds the teeth. It consists of the MANDIBLE and the MAXILLA.
Two of the masticatory muscles: the internal, or medial, pterygoid muscle and external, or lateral, pterygoid muscle. Action of the former is closing the jaws and that of the latter is opening the jaws, protruding the mandible, and moving the mandible from side to side.
Contractile tissue that produces movement in animals.
Either of a pair of bones that form the prominent part of the CHEEK and contribute to the ORBIT on each side of the SKULL.
The length of the face determined by the distance of separation of jaws. Occlusal vertical dimension (OVD or VDO) or contact vertical dimension is the lower face height with the teeth in centric occlusion. Rest vertical dimension (VDR) is the lower face height measured from a chin point to a point just below the nose, with the mandible in rest position. (From Jablonski, Dictionary of Dentistry, 1992, p250)
The mouth, teeth, jaws, pharynx, and related structures as they relate to mastication, deglutition, and speech.
Large, multinucleate single cells, either cylindrical or prismatic in shape, that form the basic unit of SKELETAL MUSCLE. They consist of MYOFIBRILS enclosed within and attached to the SARCOLEMMA. They are derived from the fusion of skeletal myoblasts (MYOBLASTS, SKELETAL) into a syncytium, followed by differentiation.
Nuclei of the trigeminal nerve situated in the brain stem. They include the nucleus of the spinal trigeminal tract (TRIGEMINAL NUCLEUS, SPINAL), the principal sensory nucleus, the mesencephalic nucleus, and the motor nucleus.
A process leading to shortening and/or development of tension in muscle tissue. Muscle contraction occurs by a sliding filament mechanism whereby actin filaments slide inward among the myosin filaments.
Recording of the changes in electric potential of muscle by means of surface or needle electrodes.
Any suction exerted by the mouth; response of the mammalian infant to draw milk from the breast. Includes sucking on inanimate objects. Not to be used for thumb sucking, which is indexed under fingersucking.
Muscles of facial expression or mimetic muscles that include the numerous muscles supplied by the facial nerve that are attached to and move the skin of the face. (From Stedman, 25th ed)
A subtype of striated muscle, attached by TENDONS to the SKELETON. Skeletal muscles are innervated and their movement can be consciously controlled. They are also called voluntary muscles.
The largest and strongest bone of the FACE constituting the lower jaw. It supports the lower teeth.
The relationship of all the components of the masticatory system in normal function. It has special reference to the position and contact of the maxillary and mandibular teeth for the highest efficiency during the excursive movements of the jaw that are essential for mastication. (From Jablonski, Dictionary of Dentistry, 1992, p556, p472)
Pain in the facial region including orofacial pain and craniofacial pain. Associated conditions include local inflammatory and neoplastic disorders and neuralgic syndromes involving the trigeminal, facial, and glossopharyngeal nerves. Conditions which feature recurrent or persistent facial pain as the primary manifestation of disease are referred to as FACIAL PAIN SYNDROMES.
Continuous involuntary sustained muscle contraction which is often a manifestation of BASAL GANGLIA DISEASES. When an affected muscle is passively stretched, the degree of resistance remains constant regardless of the rate at which the muscle is stretched. This feature helps to distinguish rigidity from MUSCLE SPASTICITY. (From Adams et al., Principles of Neurology, 6th ed, p73)
Skeletal muscle fibers characterized by their expression of the Type I MYOSIN HEAVY CHAIN isoforms which have low ATPase activity and effect several other functional properties - shortening velocity, power output, rate of tension redevelopment.
The protein constituents of muscle, the major ones being ACTINS and MYOSINS. More than a dozen accessory proteins exist including TROPONIN; TROPOMYOSIN; and DYSTROPHIN.
Myosin type II isoforms found in skeletal muscle.
Skeletal muscle structures that function as the MECHANORECEPTORS responsible for the stretch or myotactic reflex (REFLEX, STRETCH). They are composed of a bundle of encapsulated SKELETAL MUSCLE FIBERS, i.e., the intrafusal fibers (nuclear bag 1 fibers, nuclear bag 2 fibers, and nuclear chain fibers) innervated by SENSORY NEURONS.
Unstriated and unstriped muscle, one of the muscles of the internal organs, blood vessels, hair follicles, etc. Contractile elements are elongated, usually spindle-shaped cells with centrally located nuclei. Smooth muscle fibers are bound together into sheets or bundles by reticular fibers and frequently elastic nets are also abundant. (From Stedman, 25th ed)
The larger subunits of MYOSINS. The heavy chains have a molecular weight of about 230 kDa and each heavy chain is usually associated with a dissimilar pair of MYOSIN LIGHT CHAINS. The heavy chains possess actin-binding and ATPase activity.
An articulation between the condyle of the mandible and the articular tubercle of the temporal bone.
The anatomical frontal portion of the mandible, also known as the mentum, that contains the line of fusion of the two separate halves of the mandible (symphysis menti). This line of fusion divides inferiorly to enclose a triangular area called the mental protuberance. On each side, inferior to the second premolar tooth, is the mental foramen for the passage of blood vessels and a nerve.
Skeletal muscle fibers characterized by their expression of the Type II MYOSIN HEAVY CHAIN isoforms which have high ATPase activity and effect several other functional properties - shortening velocity, power output, rate of tension redevelopment. Several fast types have been identified.
A bony prominence situated on the upper surface of the body of the sphenoid bone. It houses the PITUITARY GLAND.
Developmental events leading to the formation of adult muscular system, which includes differentiation of the various types of muscle cell precursors, migration of myoblasts, activation of myogenesis and development of muscle anchorage.
Either one of the two small elongated rectangular bones that together form the bridge of the nose.
The nonstriated involuntary muscle tissue of blood vessels.
The 5th and largest cranial nerve. The trigeminal nerve is a mixed motor and sensory nerve. The larger sensory part forms the ophthalmic, mandibular, and maxillary nerves which carry afferents sensitive to external or internal stimuli from the skin, muscles, and joints of the face and mouth and from the teeth. Most of these fibers originate from cells of the TRIGEMINAL GANGLION and project to the TRIGEMINAL NUCLEUS of the brain stem. The smaller motor part arises from the brain stem trigeminal motor nucleus and innervates the muscles of mastication.
A quaternary skeletal muscle relaxant usually used in the form of its bromide, chloride, or iodide. It is a depolarizing relaxant, acting in about 30 seconds and with a duration of effect averaging three to five minutes. Succinylcholine is used in surgical, anesthetic, and other procedures in which a brief period of muscle relaxation is called for.
A symptom complex consisting of pain, muscle tenderness, clicking in the joint, and limitation or alteration of mandibular movement. The symptoms are subjective and manifested primarily in the masticatory muscles rather than the temporomandibular joint itself. Etiologic factors are uncertain but include occlusal dysharmony and psychophysiologic factors.
The measurement of the dimensions of the HEAD.
A malocclusion in which maxillary incisor and canine teeth project over the mandiblar teeth excessively. The overlap is measured perpendicular to the occlusal plane and is also called vertical overlap. When the overlap is measured parallel to the occlusal plane it is referred to as overjet.
One of a pair of irregularly shaped bones that form the upper jaw. A maxillary bone provides tooth sockets for the superior teeth, forms part of the ORBIT, and contains the MAXILLARY SINUS.
The facial skeleton, consisting of bones situated between the cranial base and the mandibular region. While some consider the facial bones to comprise the hyoid (HYOID BONE), palatine (HARD PALATE), and zygomatic (ZYGOMA) bones, MANDIBLE, and MAXILLA, others include also the lacrimal and nasal bones, inferior nasal concha, and vomer but exclude the hyoid bone. (Jablonski, Dictionary of Dentistry, 1992, p113)
The process of growth and differentiation of the jaws and face.
The curve formed by the row of TEETH in their normal position in the JAW. The inferior dental arch is formed by the mandibular teeth, and the superior dental arch by the maxillary teeth.
Methods and procedures for the diagnosis of diseases of the ear or of hearing disorders or demonstration of hearing acuity or loss.
Reference points located by visual inspection, palpation, or computer assistance, that are useful in localizing structures on or within the human body.
Congenital or acquired asymmetry of the face.
The neck muscles consist of the platysma, splenius cervicis, sternocleidomastoid(eus), longus colli, the anterior, medius, and posterior scalenes, digastric(us), stylohyoid(eus), mylohyoid(eus), geniohyoid(eus), sternohyoid(eus), omohyoid(eus), sternothyroid(eus), and thyrohyoid(eus).
General increase in bulk of a part or organ due to CELL ENLARGEMENT and accumulation of FLUIDS AND SECRETIONS, not due to tumor formation, nor to an increase in the number of cells (HYPERPLASIA).
A sensory branch of the MANDIBULAR NERVE, which is part of the trigeminal (5th cranial) nerve. The lingual nerve carries general afferent fibers from the anterior two-thirds of the tongue, the floor of the mouth, and the mandibular gingivae.
A variety of conditions affecting the anatomic and functional characteristics of the temporomandibular joint. Factors contributing to the complexity of temporomandibular diseases are its relation to dentition and mastication and the symptomatic effects in other areas which account for referred pain to the joint and the difficulties in applying traditional diagnostic procedures to temporomandibular joint pathology where tissue is rarely obtained and x-rays are often inadequate or nonspecific. Common diseases are developmental abnormalities, trauma, subluxation, luxation, arthritis, and neoplasia. (From Thoma's Oral Pathology, 6th ed, pp577-600)
A branch of the trigeminal (5th cranial) nerve. The mandibular nerve carries motor fibers to the muscles of mastication and sensory fibers to the teeth and gingivae, the face in the region of the mandible, and parts of the dura.
A condition in which certain opposing teeth fail to establish occlusal contact when the jaws are closed.
A state arrived at through prolonged and strong contraction of a muscle. Studies in athletes during prolonged submaximal exercise have shown that muscle fatigue increases in almost direct proportion to the rate of muscle glycogen depletion. Muscle fatigue in short-term maximal exercise is associated with oxygen lack and an increased level of blood and muscle lactic acid, and an accompanying increase in hydrogen-ion concentration in the exercised muscle.
The semilunar-shaped ganglion containing the cells of origin of most of the sensory fibers of the trigeminal nerve. It is situated within the dural cleft on the cerebral surface of the petrous portion of the temporal bone and gives off the ophthalmic, maxillary, and part of the mandibular nerves.
Malocclusion in which the mandible is posterior to the maxilla as reflected by the relationship of the first permanent molar (distoclusion).
The resection or removal of the innervation of a muscle or muscle tissue.
Malocclusion in which the mandible and maxilla are anteroposteriorly normal as reflected by the relationship of the first permanent molar (i.e., in neutroclusion), but in which individual teeth are abnormally related to each other.
Neurons which activate MUSCLE CELLS.
The anterior portion of the head that includes the skin, muscles, and structures of the forehead, eyes, nose, mouth, cheeks, and jaw.

Activation of peripheral GABAA receptors inhibits temporomandibular joint-evoked jaw muscle activity. (1/310)

We have previously shown that injection of mustard oil or glutamate into rat temporomandibular joint (TMJ) tissues, an experimental model of acute TMJ injury, can reflexly induce a prolonged increase in the activity of both digastric (jaw-opener) and masseter (jaw-closer) muscles. In this study, GABA was applied to the TMJ region by itself or in combination with glutamate, and the magnitude of evoked jaw muscle electromyographic (EMG) activity was measured. Application of GABA alone to the TMJ region did not evoke significant jaw muscle EMG activity when compared with normal saline controls. In contrast, co-application of GABA and glutamate into the TMJ region decreased the magnitude of glutamate-evoked EMG activity. This GABA-mediated inhibition of glutamate-evoked EMG activity followed an inverse dose-response relationship with an estimated median inhibitory dose (ID50) of 0.17 +/- 0.05 (SE) micromol and 0.031 +/- 0.006 micromol for the digastric and masseter muscles, respectively. Co-administration of the GABAA receptor antagonist bicuculline (0.05 micromol) but not the GABAB receptor antagonist phaclofen (0.05 or 0. 15 micromol) reversed the suppressive actions of GABA, indicating that this action of GABA may be mediated by peripheral GABAA receptors located within the TMJ region. Our results suggest that activation of peripheral GABAA receptors located within the TMJ region could act to decrease the transmission of nociceptive information.  (+info)

Halothane induces calcium release from human skinned masseter muscle fibers. (2/310)

BACKGROUND: An increase in masseter muscle tone in response to halothane or succinylcholine anesthesia (or both) can be observed in healthy persons. Thus the authors compared the fiber-type halothane and succinylcholine sensitivities in human masseter and vastus lateralis muscles. METHODS: Masseter and vastus lateralis muscle segments were obtained from 13 and 9 healthy persons, respectively. After chemical skinning of a single fiber and loading the sarcoplasmic reticulum with Ca++ 0.16 microM solution, halothane (0.5-4 vol% bubbled in the incubating solution), succinylcholine (0.1 microM to 10 mM), or both sensitivities were defined as the concentration inducing more than 10% of the maximum tension obtained by application of 16 microM Ca++ solution. The myofilament response to Ca++ was studied with and without halothane by observing the isometric tension of skinned masseter fibers challenged with increasing concentrations of Ca++. Muscle fiber type was determined by the difference in strontium-induced tension measurements. RESULTS: A significant difference in halothane sensitivity was found between type 1 masseter fibers (0.6+/-0.2 vol%; mean +/- SD) versus type 1 (2.7+/-0.6 vol%) and type 2 vastus lateralis muscle (2.5+/-0.4 vol%). Succinylcholine did not induce Ca++ release by the sarcoplasmic reticulum. In the masseter muscle, 0.75 vol% halothane decreased the maximal activated tension by 40% but did not change the Ca++ concentration that yields 50% of the maximal tension. CONCLUSIONS: The very low halothane threshold for Ca++ release from the masseter muscle usually could be counteracted by a direct negative inotropic effect on contractile proteins. However, halothane may increase the sensitivity of the sarcoplasmic reticulum Ca++ release to succinylcholine-induced depolarization, leading to an increase in masseter muscle tone.  (+info)

Jaw reflexes evoked by mechanical stimulation of teeth in humans. (3/310)

Jaw reflexes evoked by mechanical stimulation of teeth in humans. The reflex response of jaw muscles to mechanical stimulation of an upper incisor tooth was investigated using the surface electromyogram (SEMG) of the masseter muscle and the bite force. With a slowly rising stimulus, the reflex response obtained on the masseter SEMG showed three different patterns of reflex responses; sole excitation, sole inhibition, and inhibition followed by excitation. Simultaneously recorded bite force, however, exhibited mainly one reflex response pattern, a decrease followed by an increase in the net closing force. A rapidly rising stimulus also induced several different patterns of reflex responses in the masseter SEMG. When the simultaneously recorded bite force was analyzed, however, there was only one reflex response pattern, a decrease in the net closing force. Therefore, the reflex change in the masseter muscle is not a good representative of the net reflex response of all jaw muscles to mechanical tooth stimulation. The net response is best expressed by the averaged bite force. The averaged bite force records showed that when the stimulus force was developing rapidly, the periodontal reflex could reduce the bite force and hence protect the teeth and supporting tissues from damaging forces. It also can increase the bite force; this might help keep food between the teeth if the change in force rate is slow, especially when the initial bite force is low.  (+info)

Muscle spindle afferent input to motoneurons in human masseter. (4/310)

The H-reflex response in large and small single motor units in human deep anterior masseter was studied to investigate the distribution of muscle spindle afferents onto masseter motoneurons. We found that only the larger units displayed H-reflex responses. This indicates preferential distribution of muscle spindle input onto large motoneurons or a skewed distribution of tonic presynaptic inhibitory mechanisms.  (+info)

Jaw reflexes in healthy old people. (5/310)

OBJECTIVE: to investigate variations in the masseteric myotatic reflex (jaw-jerk) and the silent period from the 5th to the 9th decades of life. SUBJECTS AND METHODS: electromyographic data were recorded from the masseter muscle of the preferred chewing side by surface electrodes, using a computerized recording and analysis system. Chin taps were applied with a neurologist's hammer during mandibular rest and at 40% intercuspal clenching in 30 healthy people aged from 49 to 87 years. The influence of age, gender and silent period type were analysed by multiple regression analysis (P < or = 0.05). RESULTS: even in the very old subjects all reflexes were elicited, at least once. However, with increasing age the overall occurrence of the jaw-jerk reflex at rest (%) and its amplitude, at rest and at clench, were reduced, while its latency at rest was significantly increased (P < or = 0.05). No age effects were recorded in most parameters of the jaw-jerk reflex at clench and in the silent period. Women showed a tendency for reduced latencies of the jaw-jerk and the early silent period and increased silent period duration (P < or = 0.05). They also had a steeper decline in myotatic reflex activity, particularly at rest. CONCLUSION: simple masseteric reflex activity is maintained until very old age, particularly when elicited during contraction of the jaw elevators.  (+info)

Behavior of jaw muscle spindle afferents during cortically induced rhythmic jaw movements in the anesthetized rabbit. (6/310)

The regulation by muscle spindles of jaw-closing muscle activity during mastication was evaluated in anesthetized rabbits. Simultaneous records were made of the discharges of muscle spindle units in the mesencephalic trigeminal nucleus, masseter and digastric muscle activity (electromyogram [EMG]), and jaw-movement parameters during cortically induced rhythmic jaw movements. One of three test strips of polyurethane foam, each of a different hardness, was inserted between the opposing molars during the jaw movements. The induced rhythmic jaw movements were crescent shaped and were divided into three phases: jaw-opening, jaw-closing, and power. The firing rate of muscle spindle units during each phase increased after strip application, with a tendency for the spindle discharge to be continuous throughout the entire chewing cycle. However, although the firing rate did not change during the jaw-opening and jaw-closing phases when the strip hardness was altered, the firing rate during the power phase increased in a hardness-dependent manner. In addition, the integrated EMG activity, the duration of the masseteric bursts, and the minimum gape increased with strip hardness. Spindle discharge during the power phase correlated with jaw-closing muscle activity, implying that the change in jaw-closing muscle activity associated with strip hardness was caused by increased spindle discharge produced through insertion of a test strip. The increased firing rate during the other two phases may be involved in a long-latency spindle feedback. This could contribute to matching the spatiotemporal pattern of the central pattern generator to that of the moving jaw.  (+info)

Global field power helps separate respiratory-related evoked potentials from EMG contamination. (7/310)

Respiratory-related evoked potentials (RREPs) were stimulated by brief (200-ms) oral pressure pulses (-10 cmH(2)O) applied at the onset of inspiration in 12 subjects. Scalp potentials were measured at 30 sites on a rectangular grid that encompassed the right side of the scalp overlying the somatosensory cortex (SSC). Concurrent and significant masseter EMG (mEMG) activity was evoked by the pressure pulse, and we found correlational evidence for contamination of the RREP by the mEMG. The global field power (GFP) was used to provide a robust, reference-independent measure of SSC activation that provided partial insulation from mEMG contamination. The mean GFP from all subjects, reflective of afferent information from respiratory mechanoreceptors, showed a latency to onset of significant afferent SSC activity of approximately 25 ms. Scalp GFP activity during control experiments (absence of applied pressure) was significant and may reflect ongoing afferent activity from inspiration.  (+info)

Contribution of supraglottal mechanoreceptor afferents to respiratory-related evoked potentials in humans. (8/310)

We used the global field power (GFP) to estimate the magnitude and timing of activation of the somatosensory cortex by respiratory mechanoreceptor afferents in normal humans in response to brief, negative oral pressure pulses applied at the onset of inspiration. We compared responses before (test) and after insertion of a laryngeal mask airway (LMA) that prevented supraglottal airway receptors from sensing the applied stimulus. Evoked potential responses without supraglottic stimulation were smaller, with delayed or missing features, than those with all receptors stimulated. Supraglottic receptors contribute about one-half of the GFP summed over the 100 ms poststimulus, and subglottal receptors, including those in the larynx, provide a GFP response approximately 38% above baseline. The most obvious difference between test and LMA responses occurred at 55 ms on average, when the LMA GFP lacked activation features seen in the test condition. We conclude that mechanoreceptors above the larynx are responsible for a major portion of the midlatency afferent information arriving at the somatosensory cortex in response to applied pressure pulses.  (+info)

The masseter muscle is a strong chewing muscle in the jaw. It is a broad, thick, quadrilateral muscle that extends from the zygomatic arch (cheekbone) to the lower jaw (mandible). The masseter muscle has two distinct parts: the superficial part and the deep part.

The superficial part of the masseter muscle originates from the lower border of the zygomatic process of the maxilla and the anterior two-thirds of the inferior border of the zygomatic arch. The fibers of this part run almost vertically downward to insert on the lateral surface of the ramus of the mandible and the coronoid process.

The deep part of the masseter muscle originates from the deep surface of the zygomatic arch and inserts on the medial surface of the ramus of the mandible, blending with the temporalis tendon.

The primary function of the masseter muscle is to elevate the mandible, helping to close the mouth and clench the teeth together during mastication (chewing). It also plays a role in stabilizing the jaw during biting and speaking. The masseter muscle is one of the most powerful muscles in the human body relative to its size.

Masticatory muscles are a group of skeletal muscles responsible for the mastication (chewing) process in humans and other animals. They include:

1. Masseter muscle: This is the primary muscle for chewing and is located on the sides of the face, running from the lower jawbone (mandible) to the cheekbone (zygomatic arch). It helps close the mouth and elevate the mandible during chewing.

2. Temporalis muscle: This muscle is situated in the temporal region of the skull, covering the temple area. It assists in closing the jaw, retracting the mandible, and moving it sideways during chewing.

3. Medial pterygoid muscle: Located deep within the cheek, near the angle of the lower jaw, this muscle helps move the mandible forward and grind food during chewing. It also contributes to closing the mouth.

4. Lateral pterygoid muscle: Found inside the ramus (the vertical part) of the mandible, this muscle has two heads - superior and inferior. The superior head helps open the mouth by pulling the temporomandibular joint (TMJ) downwards, while the inferior head assists in moving the mandible sideways during chewing.

These muscles work together to enable efficient chewing and food breakdown, preparing it for swallowing and digestion.

The temporalis muscle is a fan-shaped muscle located in the lateral aspect of the head, in the temporal fossa region. It belongs to the group of muscles known as muscles of mastication, responsible for chewing movements. The temporalis muscle has its origin at the temporal fossa and inserts into the coronoid process and ramus of the mandible. Its main function is to retract the mandible and assist in closing the jaw.

Mastication is the medical term for the process of chewing food. It's the first step in digestion, where food is broken down into smaller pieces by the teeth, making it easier to swallow and further digest. The act of mastication involves not only the physical grinding and tearing of food by the teeth but also the mixing of the food with saliva, which contains enzymes that begin to break down carbohydrates. This process helps to enhance the efficiency of digestion and nutrient absorption in the subsequent stages of the digestive process.

Bite force refers to the amount of force or pressure that can be exerted by the teeth and jaw when biting down or clenching together. It is a measure of an individual's maximum biting strength, typically expressed in units such as pounds (lb) or newtons (N). Bite force is an important factor in various biological and medical contexts, including oral health, nutrition, and the study of animal behavior and evolution.

In humans, bite force can vary widely depending on factors such as age, sex, muscle strength, and dental health. On average, a healthy adult human male may have a maximum bite force of around 150-200 pounds (670-890 newtons), while an adult female may have a bite force of around 100-130 pounds (445-578 newtons). However, these values can vary significantly from person to person.

Abnormalities in bite force can be indicative of various medical conditions or injuries, such as temporomandibular joint disorders (TMD), muscle weakness, or neurological disorders affecting the facial muscles. Assessing and measuring bite force may also be useful in evaluating the effectiveness of dental treatments or appliances, such as dentures or orthodontic devices.

In medical terms, the jaw is referred to as the mandible (in humans and some other animals), which is the lower part of the face that holds the lower teeth in place. It's a large, horseshoe-shaped bone that forms the lower jaw and serves as a attachment point for several muscles that are involved in chewing and moving the lower jaw.

In addition to the mandible, the upper jaw is composed of two bones known as the maxillae, which fuse together at the midline of the face to form the upper jaw. The upper jaw holds the upper teeth in place and forms the roof of the mouth, as well as a portion of the eye sockets and nasal cavity.

Together, the mandible and maxillae allow for various functions such as speaking, eating, and breathing.

The pterygoid muscles are a pair of muscles located in the deep part of the lateral aspect of the nasopharynx, in the human head. They are part of the group of muscles known as the muscles of mastication, which are involved in the chewing process.

There are two sets of pterygoid muscles: the medial and lateral pterygoids. The medial pterygoids are located deep within the jaw, near the temporomandibular joint (TMJ). They originate from the medial surface of the lateral pterygoid plate of the sphenoid bone and insert onto the inner aspect of the angle of the mandible (lower jawbone). The main function of the medial pterygoids is to assist in closing the jaw and moving it forward during chewing.

The lateral pterygoids, on the other hand, are located more superficially than the medial pterygoids and are situated near the TMJ. They have two heads: the upper head originates from the greater wing of the sphenoid bone, while the lower head arises from the lateral surface of the lateral pterygoid plate. The lateral pterygoids insert onto the front part of the neck of the mandible and the disc of the TMJ. Their main function is to assist in opening the jaw and moving it sideways during chewing.

Together, the pterygoid muscles play a crucial role in the movement and function of the jaw, allowing us to chew food effectively and speak clearly.

A muscle is a soft tissue in our body that contracts to produce force and motion. It is composed mainly of specialized cells called muscle fibers, which are bound together by connective tissue. There are three types of muscles: skeletal (voluntary), smooth (involuntary), and cardiac. Skeletal muscles attach to bones and help in movement, while smooth muscles are found within the walls of organs and blood vessels, helping with functions like digestion and circulation. Cardiac muscle is the specific type that makes up the heart, allowing it to pump blood throughout the body.

The zygoma is the scientific name for the cheekbone. It is a part of the facial skeleton that forms the prominence of the cheek and houses the maxillary sinus, one of the pairs of paranasal sinuses. The zygomatic bone, also known as the malar bone, contributes to the formation of the zygoma.

The term "vertical dimension" is used in dentistry, specifically in the field of prosthodontics, to refer to the measurement of the distance between two specific points in the vertical direction when the jaw is closed. The most common measurement is the "vertical dimension of occlusion," which is the distance between the upper and lower teeth when the jaw is in a balanced and comfortable position during resting closure.

The vertical dimension is an important consideration in the design and fabrication of dental restorations, such as dentures or dental crowns, to ensure proper function, comfort, and aesthetics. Changes in the vertical dimension can occur due to various factors, including tooth loss, jaw joint disorders, or muscle imbalances, which may require correction through dental treatment.

The stomatognathic system is a term used in medicine and dentistry to refer to the coordinated functions of the mouth, jaw, and related structures. It includes the teeth, gums, tongue, palate, lips, cheeks, salivary glands, as well as the muscles of mastication (chewing), swallowing, and speech. The stomatognathic system also involves the temporomandibular joint (TMJ) and associated structures that allow for movement of the jaw. This complex system works together to enable functions such as eating, speaking, and breathing. Dysfunction in the stomatognathic system can lead to various oral health issues, including temporomandibular disorders, occlusal problems, and orofacial pain.

Skeletal muscle fibers, also known as striated muscle fibers, are the type of muscle cells that make up skeletal muscles, which are responsible for voluntary movements of the body. These muscle fibers are long, cylindrical, and multinucleated, meaning they contain multiple nuclei. They are surrounded by a connective tissue layer called the endomysium, and many fibers are bundled together into fascicles, which are then surrounded by another layer of connective tissue called the perimysium.

Skeletal muscle fibers are composed of myofibrils, which are long, thread-like structures that run the length of the fiber. Myofibrils contain repeating units called sarcomeres, which are responsible for the striated appearance of skeletal muscle fibers. Sarcomeres are composed of thick and thin filaments, which slide past each other during muscle contraction to shorten the sarcomere and generate force.

Skeletal muscle fibers can be further classified into two main types based on their contractile properties: slow-twitch (type I) and fast-twitch (type II). Slow-twitch fibers have a high endurance capacity and are used for sustained, low-intensity activities such as maintaining posture. Fast-twitch fibers, on the other hand, have a higher contractile speed and force generation capacity but fatigue more quickly and are used for powerful, explosive movements.

The trigeminal nuclei are a collection of sensory nerve cell bodies (nuclei) located in the brainstem that receive and process sensory information from the face and head, including pain, temperature, touch, and proprioception. There are four main trigeminal nuclei: the ophthalmic, maxillary, mandibular, and mesencephalic nuclei. Each nucleus is responsible for processing sensory information from specific areas of the face and head. The trigeminal nerve (cranial nerve V) carries these sensory signals to the brainstem, where they synapse with neurons in the trigeminal nuclei before being relayed to higher brain centers for further processing.

Muscle contraction is the physiological process in which muscle fibers shorten and generate force, leading to movement or stability of a body part. This process involves the sliding filament theory where thick and thin filaments within the sarcomeres (the functional units of muscles) slide past each other, facilitated by the interaction between myosin heads and actin filaments. The energy required for this action is provided by the hydrolysis of adenosine triphosphate (ATP). Muscle contractions can be voluntary or involuntary, and they play a crucial role in various bodily functions such as locomotion, circulation, respiration, and posture maintenance.

Electromyography (EMG) is a medical diagnostic procedure that measures the electrical activity of skeletal muscles during contraction and at rest. It involves inserting a thin needle electrode into the muscle to record the electrical signals generated by the muscle fibers. These signals are then displayed on an oscilloscope and may be heard through a speaker.

EMG can help diagnose various neuromuscular disorders, such as muscle weakness, numbness, or pain, and can distinguish between muscle and nerve disorders. It is often used in conjunction with other diagnostic tests, such as nerve conduction studies, to provide a comprehensive evaluation of the nervous system.

EMG is typically performed by a neurologist or a physiatrist, and the procedure may cause some discomfort or pain, although this is usually minimal. The results of an EMG can help guide treatment decisions and monitor the progression of neuromuscular conditions over time.

"Sucking behavior" is not a term typically used in medical terminology. However, in the context of early childhood development and behavior, "non-nutritive sucking" is a term that may be used to describe an infant or young child's habitual sucking on their thumb, fingers, or pacifiers, beyond what is necessary for feeding. This type of sucking behavior can provide a sense of security, comfort, or help to self-soothe and manage stress or anxiety.

It's important to note that while non-nutritive sucking is generally considered a normal part of early childhood development, persistent sucking habits beyond the age of 2-4 years may lead to dental or orthodontic problems such as an overbite or open bite. Therefore, it's recommended to monitor and address these behaviors if they persist beyond this age range.

Facial muscles, also known as facial nerves or cranial nerve VII, are a group of muscles responsible for various expressions and movements of the face. These muscles include:

1. Orbicularis oculi: muscle that closes the eyelid and raises the upper eyelid
2. Corrugator supercilii: muscle that pulls the eyebrows down and inward, forming wrinkles on the forehead
3. Frontalis: muscle that raises the eyebrows and forms horizontal wrinkles on the forehead
4. Procerus: muscle that pulls the medial ends of the eyebrows downward, forming vertical wrinkles between the eyebrows
5. Nasalis: muscle that compresses or dilates the nostrils
6. Depressor septi: muscle that pulls down the tip of the nose
7. Levator labii superioris alaeque nasi: muscle that raises the upper lip and flares the nostrils
8. Levator labii superioris: muscle that raises the upper lip
9. Zygomaticus major: muscle that raises the corner of the mouth, producing a smile
10. Zygomaticus minor: muscle that raises the nasolabial fold and corner of the mouth
11. Risorius: muscle that pulls the angle of the mouth laterally, producing a smile
12. Depressor anguli oris: muscle that pulls down the angle of the mouth
13. Mentalis: muscle that raises the lower lip and forms wrinkles on the chin
14. Buccinator: muscle that retracts the cheek and helps with chewing
15. Platysma: muscle that depresses the corner of the mouth and wrinkles the skin of the neck.

These muscles are innervated by the facial nerve, which arises from the brainstem and exits the skull through the stylomastoid foramen. Damage to the facial nerve can result in facial paralysis or weakness on one or both sides of the face.

Skeletal muscle, also known as striated or voluntary muscle, is a type of muscle that is attached to bones by tendons or aponeuroses and functions to produce movements and support the posture of the body. It is composed of long, multinucleated fibers that are arranged in parallel bundles and are characterized by alternating light and dark bands, giving them a striped appearance under a microscope. Skeletal muscle is under voluntary control, meaning that it is consciously activated through signals from the nervous system. It is responsible for activities such as walking, running, jumping, and lifting objects.

The mandible, also known as the lower jaw, is the largest and strongest bone in the human face. It forms the lower portion of the oral cavity and plays a crucial role in various functions such as mastication (chewing), speaking, and swallowing. The mandible is a U-shaped bone that consists of a horizontal part called the body and two vertical parts called rami.

The mandible articulates with the skull at the temporomandibular joints (TMJs) located in front of each ear, allowing for movements like opening and closing the mouth, protrusion, retraction, and side-to-side movement. The mandible contains the lower teeth sockets called alveolar processes, which hold the lower teeth in place.

In medical terminology, the term "mandible" refers specifically to this bone and its associated structures.

Dental occlusion refers to the alignment and contact between the upper and lower teeth when the jaws are closed. It is the relationship between the maxillary (upper) and mandibular (lower) teeth when they approach each other, as occurs during chewing or biting.

A proper dental occlusion, also known as a balanced occlusion, ensures that the teeth and jaw joints function harmoniously, reducing the risk of tooth wear, damage, and temporomandibular disorders (TMD). Malocclusion, on the other hand, refers to improper alignment or contact between the upper and lower teeth, which may require orthodontic treatment or dental restorations to correct.

Facial pain is a condition characterized by discomfort or pain felt in any part of the face. It can result from various causes, including nerve damage or irritation, injuries, infections, dental problems, migraines, or sinus congestion. The pain can range from mild to severe and may be sharp, dull, constant, or intermittent. In some cases, facial pain can also be associated with other symptoms such as headaches, redness, swelling, or changes in sensation. Accurate diagnosis and treatment of the underlying cause are essential for effective management of facial pain.

Muscle rigidity is a term used to describe an increased resistance to passive movement or muscle tone that is present at rest, which cannot be overcome by the person. It is a common finding in various neurological conditions such as Parkinson's disease, stiff-person syndrome, and tetanus. In these conditions, muscle rigidity can result from hyperexcitability of the stretch reflex arc or abnormalities in the basal ganglia circuitry.

Muscle rigidity should be distinguished from spasticity, which is a velocity-dependent increase in muscle tone that occurs during voluntary movement or passive stretching. Spasticity is often seen in upper motor neuron lesions such as stroke or spinal cord injury.

It's important to note that the assessment of muscle rigidity requires a careful physical examination and may need to be evaluated in conjunction with other signs and symptoms to determine an underlying cause.

Slow-twitch muscle fibers, also known as type I muscle fibers, are specialized skeletal muscle cells that contract relatively slowly and generate less force than fast-twitch fibers. However, they can maintain contraction for longer periods of time and have a higher resistance to fatigue. These fibers primarily use oxygen and aerobic metabolism to produce energy, making them highly efficient during prolonged, lower-intensity activities such as long-distance running or cycling. Slow-twitch muscle fibers also have an abundant blood supply, which allows for efficient delivery of oxygen and removal of waste products.

Muscle proteins are a type of protein that are found in muscle tissue and are responsible for providing structure, strength, and functionality to muscles. The two major types of muscle proteins are:

1. Contractile proteins: These include actin and myosin, which are responsible for the contraction and relaxation of muscles. They work together to cause muscle movement by sliding along each other and shortening the muscle fibers.
2. Structural proteins: These include titin, nebulin, and desmin, which provide structural support and stability to muscle fibers. Titin is the largest protein in the human body and acts as a molecular spring that helps maintain the integrity of the sarcomere (the basic unit of muscle contraction). Nebulin helps regulate the length of the sarcomere, while desmin forms a network of filaments that connects adjacent muscle fibers together.

Overall, muscle proteins play a critical role in maintaining muscle health and function, and their dysregulation can lead to various muscle-related disorders such as muscular dystrophy, myopathies, and sarcopenia.

Skeletal muscle myosin, also known as myosin II, is a type of motor protein that plays a crucial role in muscle contraction. It is a hexameric protein composed of two heavy chains and four light chains. The heavy chains have a head region, which contains the ATPase activity and binds to actin filaments, and a tail region, which forms a coiled-coil structure that allows myosin molecules to self-associate into thick filaments.

During muscle contraction, the myosin heads bind to actin filaments in the sarcomere and undergo a power stroke, which results in the sliding of the actin filaments relative to the myosin filaments and thus shortening of the sarcomere. The ATP hydrolysis provides the energy for this power stroke.

Skeletal muscle myosin is essential for generating force and movement in skeletal muscles, and its dysfunction can lead to various muscle diseases and disorders.

Muscle spindles are specialized sensory organs found within the muscle belly, which primarily function as proprioceptors, providing information about the length and rate of change in muscle length. They consist of small, encapsulated bundles of intrafusal muscle fibers that are interspersed among the extrafusal muscle fibers (the ones responsible for force generation).

Muscle spindles have two types of sensory receptors called primary and secondary endings. Primary endings are located near the equatorial region of the intrafusal fiber, while secondary endings are situated more distally. These endings detect changes in muscle length and transmit this information to the central nervous system (CNS) through afferent nerve fibers.

The activation of muscle spindles plays a crucial role in reflexive responses, such as the stretch reflex (myotatic reflex), which helps maintain muscle tone and joint stability. Additionally, they contribute to our sense of body position and movement awareness, known as kinesthesia.

Smooth muscle, also known as involuntary muscle, is a type of muscle that is controlled by the autonomic nervous system and functions without conscious effort. These muscles are found in the walls of hollow organs such as the stomach, intestines, bladder, and blood vessels, as well as in the eyes, skin, and other areas of the body.

Smooth muscle fibers are shorter and narrower than skeletal muscle fibers and do not have striations or sarcomeres, which give skeletal muscle its striped appearance. Smooth muscle is controlled by the autonomic nervous system through the release of neurotransmitters such as acetylcholine and norepinephrine, which bind to receptors on the smooth muscle cells and cause them to contract or relax.

Smooth muscle plays an important role in many physiological processes, including digestion, circulation, respiration, and elimination. It can also contribute to various medical conditions, such as hypertension, gastrointestinal disorders, and genitourinary dysfunction, when it becomes overactive or underactive.

Myosin Heavy Chains are the large, essential components of myosin molecules, which are responsible for the molecular motility in muscle cells. These heavy chains have a molecular weight of approximately 200 kDa and form the motor domain of myosin, which binds to actin filaments and hydrolyzes ATP to generate force and movement during muscle contraction. There are several different types of myosin heavy chains, each with specific roles in various tissues and cellular functions. In skeletal and cardiac muscles, for example, myosin heavy chains have distinct isoforms that contribute to the contractile properties of these tissues.

The temporomandibular joint (TMJ) is the articulation between the mandible (lower jaw) and the temporal bone of the skull. It's a complex joint that involves the movement of two bones, several muscles, and various ligaments. The TMJ allows for movements like rotation and translation, enabling us to open and close our mouth, chew, speak, and yawn. Dysfunction in this joint can lead to temporomandibular joint disorders (TMD), which can cause pain, discomfort, and limited jaw movement.

The "chin" is the lower, prominent part of the front portion of the jaw in humans and other animals. In medical terms, it is often referred to as the mentum or the symphysis of the mandible. The chin helps in protecting the soft tissues of the mouth and throat during activities such as eating, speaking, and swallowing. It also plays a role in shaping the overall appearance of the face. Anatomically, the chin is formed by the fusion of the two halves of the mandible (lower jawbone) at the symphysis menti.

Fast-twitch muscle fibers, also known as type II fibers, are a type of skeletal muscle fiber that are characterized by their rapid contraction and relaxation rates. These fibers have a larger diameter and contain a higher concentration of glycogen, which serves as a quick source of energy for muscle contractions. Fast-twitch fibers are further divided into two subcategories: type IIa and type IIb (or type IIx). Type IIa fibers have a moderate amount of mitochondria and can utilize both aerobic and anaerobic metabolic pathways, making them fatigue-resistant. Type IIb fibers, on the other hand, have fewer mitochondria and primarily use anaerobic metabolism, leading to faster fatigue. Fast-twitch fibers are typically used in activities that require quick, powerful movements such as sprinting or weightlifting.

The Sella Turcica, also known as the Turkish saddle, is a depression or fossa in the sphenoid bone located at the base of the skull. It forms a housing for the pituitary gland, which is a small endocrine gland often referred to as the "master gland" because it controls other glands and makes several essential hormones. The Sella Turcica has a saddle-like shape, with its anterior and posterior clinoids forming the front and back of the saddle, respectively. This region is of significant interest in neuroimaging and clinical settings, as various conditions such as pituitary tumors or other abnormalities may affect the size, shape, and integrity of the Sella Turcica.

Muscle development, also known as muscle hypertrophy, refers to the increase in size and mass of the muscles through a process called myofiber growth. This is primarily achieved through resistance or strength training exercises that cause micro-tears in the muscle fibers, leading to an inflammatory response and the release of hormones that promote muscle growth. As the muscles repair themselves, they become larger and stronger than before. Proper nutrition, including adequate protein intake, and rest are also essential components of muscle development.

It is important to note that while muscle development can lead to an increase in strength and muscular endurance, it does not necessarily result in improved athletic performance or overall fitness. A well-rounded exercise program that includes cardiovascular activity, flexibility training, and resistance exercises is recommended for optimal health and fitness outcomes.

The nasal bones are a pair of small, thin bones located in the upper part of the face, specifically in the middle of the nose. They articulate with each other at the nasal bridge and with the frontal bone above, the maxillae (upper jaw bones) on either side, and the septal cartilage inside the nose. The main function of the nasal bones is to form the bridge of the nose and protect the nasal cavity. Any damage to these bones can result in a fracture or broken nose.

A smooth muscle within the vascular system refers to the involuntary, innervated muscle that is found in the walls of blood vessels. These muscles are responsible for controlling the diameter of the blood vessels, which in turn regulates blood flow and blood pressure. They are called "smooth" muscles because their individual muscle cells do not have the striations, or cross-striped patterns, that are observed in skeletal and cardiac muscle cells. Smooth muscle in the vascular system is controlled by the autonomic nervous system and by hormones, and can contract or relax slowly over a period of time.

The trigeminal nerve, also known as the fifth cranial nerve or CNV, is a paired nerve that carries both sensory and motor information. It has three major branches: ophthalmic (V1), maxillary (V2), and mandibular (V3). The ophthalmic branch provides sensation to the forehead, eyes, and upper portion of the nose; the maxillary branch supplies sensation to the lower eyelid, cheek, nasal cavity, and upper lip; and the mandibular branch is responsible for sensation in the lower lip, chin, and parts of the oral cavity, as well as motor function to the muscles involved in chewing. The trigeminal nerve plays a crucial role in sensations of touch, pain, temperature, and pressure in the face and mouth, and it also contributes to biting, chewing, and swallowing functions.

Succinylcholine is a neuromuscular blocking agent, a type of muscle relaxant used in anesthesia during surgical procedures. It works by inhibiting the transmission of nerve impulses at the neuromuscular junction, leading to temporary paralysis of skeletal muscles. This facilitates endotracheal intubation and mechanical ventilation during surgery. Succinylcholine has a rapid onset of action and is metabolized quickly, making it useful for short surgical procedures. However, its use may be associated with certain adverse effects, such as increased heart rate, muscle fasciculations, and potentially life-threatening hyperkalemia in susceptible individuals.

Temporomandibular Joint Dysfunction Syndrome, often abbreviated as TMJD or TMD, is a group of conditions that cause pain and dysfunction in the temporomandibular joint (TMJ) - the joint that connects the jawbone to the skull. Here's a more detailed medical definition:

Temporomandibular Joint Dysfunction Syndrome is a complex disorder characterized by pain, clicking, popping, or grating sounds in the TMJ; limited movement or locking of the jaw; and/or painful chewing movements. The condition may be caused by a variety of factors, including muscle tension, joint inflammation, structural problems with the joint itself, or injury to the head, neck, or jaw.

Symptoms of TMJD can include:
- Pain or tenderness in the face, jaw joint area, neck, and/or shoulders
- Limited ability to open the mouth wide
- Jaw locking, making it difficult to close or open the mouth
- Clicking, popping, or grating sounds in the TMJ when opening or closing the mouth
- A significant change in the way the upper and lower teeth fit together
- Headaches, earaches, dizziness, and hearing problems

Treatment for TMJD can vary depending on the severity of the condition and its underlying cause. It may include self-care practices such as eating soft foods, avoiding extreme jaw movements, and practicing relaxation techniques; physical therapy; medication to reduce pain and inflammation; dental treatments such as mouthguards or bite adjustments; and, in rare cases, surgery.

Cephalometry is a medical term that refers to the measurement and analysis of the skull, particularly the head face relations. It is commonly used in orthodontics and maxillofacial surgery to assess and plan treatment for abnormalities related to the teeth, jaws, and facial structures. The process typically involves taking X-ray images called cephalograms, which provide a lateral view of the head, and then using various landmarks and reference lines to make measurements and evaluate skeletal and dental relationships. This information can help clinicians diagnose problems, plan treatment, and assess treatment outcomes.

An overbite, also known as "malocclusion of class II division 1" in dental terminology, is an orthodontic condition where the upper front teeth excessively overlap the lower front teeth when biting down. This means that the upper incisors are positioned too far forward or the lower incisors are too far back. A slight overbite is considered normal and healthy, as it allows the front teeth to perform their functions properly, such as biting and tearing food. However, a significant overbite can lead to various problems like difficulty in chewing, speaking, and maintaining good oral hygiene. It may also cause wear and tear on the teeth, jaw pain, or even contribute to temporomandibular joint disorders (TMD). Orthodontic treatment, such as braces or aligners, is often recommended to correct a severe overbite and restore proper bite alignment.

The maxilla is a paired bone that forms the upper jaw in vertebrates. In humans, it is a major bone in the face and plays several important roles in the craniofacial complex. Each maxilla consists of a body and four processes: frontal process, zygomatic process, alveolar process, and palatine process.

The maxillae contribute to the formation of the eye sockets (orbits), nasal cavity, and the hard palate of the mouth. They also contain the upper teeth sockets (alveoli) and help form the lower part of the orbit and the cheekbones (zygomatic arches).

Here's a quick rundown of its key functions:

1. Supports the upper teeth and forms the upper jaw.
2. Contributes to the formation of the eye sockets, nasal cavity, and hard palate.
3. Helps shape the lower part of the orbit and cheekbones.
4. Partakes in the creation of important sinuses, such as the maxillary sinus, which is located within the body of the maxilla.

The facial bones, also known as the facial skeleton, are a series of bones that make up the framework of the face. They include:

1. Frontal bone: This bone forms the forehead and the upper part of the eye sockets.
2. Nasal bones: These two thin bones form the bridge of the nose.
3. Maxilla bones: These are the largest bones in the facial skeleton, forming the upper jaw, the bottom of the eye sockets, and the sides of the nose. They also contain the upper teeth.
4. Zygomatic bones (cheekbones): These bones form the cheekbones and the outer part of the eye sockets.
5. Palatine bones: These bones form the back part of the roof of the mouth, the side walls of the nasal cavity, and contribute to the formation of the eye socket.
6. Inferior nasal conchae: These are thin, curved bones that form the lateral walls of the nasal cavity and help to filter and humidify air as it passes through the nose.
7. Lacrimal bones: These are the smallest bones in the skull, located at the inner corner of the eye socket, and help to form the tear duct.
8. Mandible (lower jaw): This is the only bone in the facial skeleton that can move. It holds the lower teeth and forms the chin.

These bones work together to protect vital structures such as the eyes, brain, and nasal passages, while also providing attachment points for muscles that control chewing, expression, and other facial movements.

Maxillofacial development refers to the growth and formation of the bones, muscles, and soft tissues that make up the face and jaw (maxillofacial region). This process begins in utero and continues throughout childhood and adolescence. It involves the coordinated growth and development of multiple structures, including the upper and lower jaws (maxilla and mandible), facial bones, teeth, muscles, and nerves.

Abnormalities in maxillofacial development can result in a range of conditions, such as cleft lip and palate, jaw deformities, and craniofacial syndromes. These conditions may affect a person's appearance, speech, chewing, and breathing, and may require medical or surgical intervention to correct.

Healthcare professionals involved in the diagnosis and treatment of maxillofacial developmental disorders include oral and maxillofacial surgeons, orthodontists, pediatricians, geneticists, and other specialists.

The dental arch refers to the curved shape formed by the upper or lower teeth when they come together. The dental arch follows the curve of the jaw and is important for proper bite alignment and overall oral health. The dental arches are typically described as having a U-shaped appearance, with the front teeth forming a narrower section and the back teeth forming a wider section. The shape and size of the dental arch can vary from person to person, and any significant deviations from the typical shape or size may indicate an underlying orthodontic issue that requires treatment.

Diagnostic techniques in otology refer to the methods and tests used by healthcare professionals to identify and diagnose various conditions related to the ear. These techniques can include:

1. Otoscopy: A visual examination of the external auditory canal and eardrum using an otoscope. This helps to identify any physical abnormalities, such as wax buildup, inflammation, or foreign objects in the ear.
2. Audiometry: A hearing test that measures a person's ability to hear different sounds, pitches, and volumes. This can help to identify any hearing loss or auditory processing issues.
3. Tympanometry: A test that measures the function of the middle ear by creating variations in air pressure in the ear canal. This can help to identify any issues with the eardrum or middle ear bones.
4. Acoustic reflex testing: A test that measures the body's involuntary response to loud sounds. This can help to identify any damage to the hearing nerves or brainstem.
5. Otoacoustic emissions (OAE) testing: A test that measures the sound waves produced by the inner ear in response to stimuli. This can help to identify any issues with the cochlea or hair cells in the inner ear.
6. Auditory brainstem response (ABR) testing: A test that measures the electrical activity of the hearing nerve and brainstem in response to sound. This can help to identify any issues with the auditory nervous system.
7. Vestibular testing: A series of tests that measure a person's balance and equilibrium. This can help to identify any issues with the vestibular system, which is responsible for maintaining balance.

These diagnostic techniques are used to diagnose various otological conditions such as hearing loss, tinnitus, vertigo, ear infections, and tumors of the ear.

Anatomic landmarks are specific, identifiable structures or features on the body that are used as references in medicine and surgery. These landmarks can include bones, muscles, joints, or other visible or palpable features that help healthcare professionals identify specific locations, orient themselves during procedures, or measure changes in the body.

Examples of anatomic landmarks include:

* The anterior iliac spine, a bony prominence on the front of the pelvis that can be used to locate the hip joint.
* The cubital fossa, a depression at the elbow where the median nerve and brachial artery can be palpated.
* The navel (umbilicus), which serves as a reference point for measuring distances in the abdomen.
* The xiphoid process, a small piece of cartilage at the bottom of the breastbone that can be used to locate the heart and other structures in the chest.

Anatomic landmarks are important for accurate diagnosis, treatment planning, and surgical procedures, as they provide reliable and consistent reference points that can help ensure safe and effective care.

Facial asymmetry refers to a condition in which the facial features are not identical or proportionate on both sides of a vertical line drawn down the middle of the face. This can include differences in the size, shape, or positioning of facial features such as the eyes, ears, nose, cheeks, and jaw. Facial asymmetry can be mild and barely noticeable, or it can be more severe and affect a person's appearance and/or functionality of the mouth and jaw.

Facial asymmetry can be present at birth (congenital) or can develop later in life due to various factors such as injury, surgery, growth disorders, nerve damage, or tumors. In some cases, facial asymmetry may not cause any medical problems and may only be of cosmetic concern. However, in other cases, it may indicate an underlying medical condition that requires treatment.

Depending on the severity and cause of the facial asymmetry, treatment options may include cosmetic procedures such as fillers or surgery, orthodontic treatment, physical therapy, or medication to address any underlying conditions.

Neck muscles, also known as cervical muscles, are a group of muscles that provide movement, support, and stability to the neck region. They are responsible for various functions such as flexion, extension, rotation, and lateral bending of the head and neck. The main neck muscles include:

1. Sternocleidomastoid: This muscle is located on either side of the neck and is responsible for rotating and flexing the head. It also helps in tilting the head to the same side.

2. Trapezius: This large, flat muscle covers the back of the neck, shoulders, and upper back. It is involved in movements like shrugging the shoulders, rotating and extending the head, and stabilizing the scapula (shoulder blade).

3. Scalenes: These three pairs of muscles are located on the side of the neck and assist in flexing, rotating, and laterally bending the neck. They also help with breathing by elevating the first two ribs during inspiration.

4. Suboccipitals: These four small muscles are located at the base of the skull and are responsible for fine movements of the head, such as tilting and rotating.

5. Longus Colli and Longus Capitis: These muscles are deep neck flexors that help with flexing the head and neck forward.

6. Splenius Capitis and Splenius Cervicis: These muscles are located at the back of the neck and assist in extending, rotating, and laterally bending the head and neck.

7. Levator Scapulae: This muscle is located at the side and back of the neck, connecting the cervical vertebrae to the scapula. It helps with rotation, extension, and elevation of the head and scapula.

Hypertrophy, in the context of physiology and pathology, refers to an increase in the size of an organ or tissue due to an enlargement of its constituent cells. It is often used to describe the growth of muscle cells (myocytes) in response to increased workload or hormonal stimulation, resulting in an increase in muscle mass. However, hypertrophy can also occur in other organs such as the heart (cardiac hypertrophy) in response to high blood pressure or valvular heart disease.

It is important to note that while hypertrophy involves an increase in cell size, hyperplasia refers to an increase in cell number. In some cases, both hypertrophy and hyperplasia can occur together, leading to a significant increase in the overall size and function of the organ or tissue.

The lingual nerve is a branch of the mandibular division of the trigeminal nerve (cranial nerve V). It provides general sensory innervation to the anterior two-thirds of the tongue, including taste sensation from the same region. It also supplies sensory innervation to the floor of the mouth and the lingual gingiva (gum tissue). The lingual nerve is closely associated with the submandibular and sublingual salivary glands and their ducts.

Temporomandibular Joint Disorders (TMD) refer to a group of conditions that cause pain and dysfunction in the temporomandibular joint (TMJ) and the muscles that control jaw movement. The TMJ is the hinge joint that connects the lower jaw (mandible) to the skull (temporal bone) in front of the ear. It allows for movements required for activities such as eating, speaking, and yawning.

TMD can result from various causes, including:

1. Muscle tension or spasm due to clenching or grinding teeth (bruxism), stress, or jaw misalignment
2. Dislocation or injury of the TMJ disc, which is a small piece of cartilage that acts as a cushion between the bones in the joint
3. Arthritis or other degenerative conditions affecting the TMJ
4. Bite problems (malocclusion) leading to abnormal stress on the TMJ and its surrounding muscles
5. Stress, which can exacerbate existing TMD symptoms by causing muscle tension

Symptoms of Temporomandibular Joint Disorders may include:
- Pain or tenderness in the jaw, face, neck, or shoulders
- Limited jaw movement or locking of the jaw
- Clicking, popping, or grating sounds when moving the jaw
- Headaches, earaches, or dizziness
- Difficulty chewing or biting
- Swelling on the side of the face

Treatment for TMD varies depending on the severity and cause of the condition. It may include self-care measures (like eating soft foods, avoiding extreme jaw movements, and applying heat or cold packs), physical therapy, medications (such as muscle relaxants, pain relievers, or anti-inflammatory drugs), dental work (including bite adjustments or orthodontic treatment), or even surgery in severe cases.

The mandibular nerve is a branch of the trigeminal nerve (the fifth cranial nerve), which is responsible for sensations in the face and motor functions such as biting and chewing. The mandibular nerve provides both sensory and motor innervation to the lower third of the face, below the eye and nose down to the chin.

More specifically, it carries sensory information from the lower teeth, lower lip, and parts of the oral cavity, as well as the skin over the jaw and chin. It also provides motor innervation to the muscles of mastication (chewing), which include the masseter, temporalis, medial pterygoid, and lateral pterygoid muscles.

Damage to the mandibular nerve can result in numbness or loss of sensation in the lower face and mouth, as well as weakness or difficulty with chewing and biting.

An open bite, in dental terminology, refers to a type of malocclusion (or misalignment) where the upper and lower teeth do not make contact with each other when the jaw is closed. More specifically, the front teeth of both the upper and lower jaws fail to meet or overlap normally, creating an opening in the bite. This condition can lead to various problems such as difficulty in biting, chewing, speaking clearly, and even cause temporomandibular joint disorders (TMD). Open bite can be caused by several factors including thumb sucking, tongue thrusting, genetic factors, or abnormal jaw development. Treatment usually involves orthodontic intervention, possibly with the use of appliances or even surgery in severe cases.

Muscle fatigue is a condition characterized by a reduction in the ability of a muscle to generate force or power, typically after prolonged or strenuous exercise. It is often accompanied by sensations of tiredness, weakness, and discomfort in the affected muscle(s). The underlying mechanisms of muscle fatigue are complex and involve both peripheral factors (such as changes in muscle metabolism, ion handling, and neuromuscular transmission) and central factors (such as changes in the nervous system's ability to activate muscles). Muscle fatigue can also occur as a result of various medical conditions or medications that impair muscle function.

The trigeminal ganglion, also known as the semilunar or Gasserian ganglion, is a sensory ganglion (a cluster of nerve cell bodies) located near the base of the skull. It is a part of the trigeminal nerve (the fifth cranial nerve), which is responsible for sensation in the face and motor functions such as biting and chewing.

The trigeminal ganglion contains the cell bodies of sensory neurons that carry information from three major branches of the trigeminal nerve: the ophthalmic, maxillary, and mandibular divisions. These divisions provide sensation to different areas of the face, head, and oral cavity, including the skin, mucous membranes, muscles, and teeth.

Damage to the trigeminal ganglion or its nerve branches can result in various sensory disturbances, such as pain, numbness, or tingling in the affected areas. Conditions like trigeminal neuralgia, a disorder characterized by intense, stabbing facial pain, may involve the trigeminal ganglion and its associated nerves.

Malocclusion, Angle Class II is a type of dental malocclusion where the relationship between the maxilla (upper jaw) and mandible (lower jaw) is such that the lower molar teeth are positioned posteriorly relative to the upper molar teeth. This results in an overbite, which means that the upper front teeth overlap the lower front teeth excessively. The classification was proposed by Edward Angle, an American orthodontist who is considered the father of modern orthodontics. In this classification system, Class II malocclusion is further divided into three subclasses (I, II, and III) based on the position of the lower incisors relative to the upper incisors.

Muscle denervation is a medical term that refers to the loss of nerve supply to a muscle or group of muscles. This can occur due to various reasons, such as injury to the nerves, nerve compression, or certain medical conditions like neuromuscular disorders. When the nerve supply to the muscle is interrupted, it can lead to muscle weakness, atrophy (wasting), and ultimately, paralysis.

In denervation, the communication between the nervous system and the muscle is disrupted, which means that the muscle no longer receives signals from the brain to contract and move. Over time, this can result in significant muscle wasting and disability, depending on the severity and extent of the denervation.

Denervation may be treated with various therapies, including physical therapy, medication, or surgical intervention, such as nerve grafting or muscle transfers, to restore function and prevent further muscle wasting. The specific treatment approach will depend on the underlying cause and severity of the denervation.

Malocclusion, Angle Class I is a type of dental malocclusion where the misalignment of teeth is not severe enough to affect the overall function or appearance of the bite significantly. Named after Edward Angle, the founder of modern orthodontics, this classification indicates that the mesiobuccal cusp of the upper first molar is aligned with the buccal groove of the lower first molar. Although the bite appears normal, there might be crowding, spacing, or rotations present in the teeth, which can lead to aesthetic concerns and potential periodontal issues if left untreated.

Motor neurons are specialized nerve cells in the brain and spinal cord that play a crucial role in controlling voluntary muscle movements. They transmit electrical signals from the brain to the muscles, enabling us to perform actions such as walking, talking, and swallowing. There are two types of motor neurons: upper motor neurons, which originate in the brain's motor cortex and travel down to the brainstem and spinal cord; and lower motor neurons, which extend from the brainstem and spinal cord to the muscles. Damage or degeneration of these motor neurons can lead to various neurological disorders, such as amyotrophic lateral sclerosis (ALS) and spinal muscular atrophy (SMA).

In medical terms, the face refers to the front part of the head that is distinguished by the presence of the eyes, nose, and mouth. It includes the bones of the skull (frontal bone, maxilla, zygoma, nasal bones, lacrimal bones, palatine bones, inferior nasal conchae, and mandible), muscles, nerves, blood vessels, skin, and other soft tissues. The face plays a crucial role in various functions such as breathing, eating, drinking, speaking, seeing, smelling, and expressing emotions. It also serves as an important identifier for individuals, allowing them to be recognized by others.

The most obvious muscle of mastication is the masseter muscle, since it is the most superficial and one of the strongest. The ... musculus masseter. The action of the muscle during bilateral contraction of the entire muscle is to elevate the mandible, ... showing the masseter muscle and neighbors. Zygomasseteric system The word masseter (usually /məˈsiːtər/, sometimes /ˈmæsɪtər/) ... The masseter muscle can become enlarged in patients who habitually clench or grind (with bruxism) their teeth and even in those ...
... weak chewing muscles (masseter); weak lip muscles (orbicularis oris); overdeveloped chin muscles (mentalis); muscular imbalance ... and facial muscle patterns that promote correct gestures for chewing and eating Retrain oral, lingual, and facial muscles to ... Other causes of open-mouth posture are the weakness of lip muscles, overall lack of tone in the body or hypotonia, and ... Mouth breathing can particularly affect the growing face, as the abnormal pull of these muscle groups on facial bones slowly ...
It passes through the mandibular notch to reach masseter muscle. It provides motor innervation the masseter muscle, and sensory ... then entering the muscle. The masseteric nerve provides motor innervation the masseter muscle. It additionally sends articular ... the mandibular notch alongside the masseteric artery before branching out upon the surface of the masseter muscle, ... It passes laterally superior to the lateral pterygoid muscle, anterior to the temporomandibular joint, and posterior to the ...
The dissection cuts the platysma and the masseter muscle. As the skin dissection is done, a small protrude of the ramus could ... The mandibular setback surgery improves one's masticatory muscle activity and speech intelligibility. The mandibular setback ...
The ECMs were focussed on the masseter muscle and temporalis muscle. Females showed a significantly higher amplitude - meaning ... In response, the masseter muscles will jerk the mandible upwards. Normally this reflex is absent or very slight. However, in ... Jaw muscles do not display very prominent changes in muscular tissue with age in healthy elderly, as their oral cavities are in ... The jaw jerk reflex or the masseter reflex is a stretch reflex used to test the status of a patient's trigeminal nerve (cranial ...
It is superficial to the masseter muscle, partially overlying it. The risorius muscle draws the angle of the mouth lateral-ward ... Because it partially overlies the masseter muscle, it may be unintentionally affected during botox injections, resulting in ... The risorius muscle is a highly variable muscle of facial expression. It has numerous and very variable origins, and inserts ... The risorius muscle is highly variable. It ranges in form from one or more slender bundles to a wide (yet thin) fan. It may be ...
Abdala, F.; Damiani, R. (2004). "Early development of the mammalian superficial masseter muscle in cynodonts". Palaeontologica ... Visible striations and scars infer the muscle attachment points on both epicondyles. A large entepicondylar foramen can be ... fossa on the dentary preserved in Platycraniellus represents higher bite force since this feature allows more masseteric muscle ...
... masseter, and pterygoid muscles. The disease is usually bilateral. MMM is caused by the presence of 2M fibers in the muscles of ... Most Commonly Asked Questions about Masticatory Muscle Myositis Masticatory muscle myositis (MMM), Dogs Masticatory Muscle ... Diagnosis of MMM is through either biopsy of the temporalis or masseter muscles or the 2M antibody assay, in which blood serum ... Masticatory muscle myositis (MMM) is an inflammatory disease in dogs affecting the muscles of mastication (chewing). It is also ...
The masseter muscle does not pass through the infraorbital canal; it cannot due to the position of the canal. Some authorities ... The masseter muscle does attach directly behind the zygomatic arch in a manner very different from sciuromorphs. Some ...
The masseter muscle inserts into a large and deep masseteric fossa. Two mandibular foramina are present, a larger one located ... A powerful digastric muscle is inserted in the marginal process, and a shallow depression along the posterior ventral border ...
The defining feature is muscle diastasis which is separation of the masseter. This phenotype can also be partially corrected ... The facial cleft in this case results in a more severe muscle separation even though there is not a true open cleft. Bones in ... This version of macrostomia is less severe because it does not affect the facial muscles and is not associated with any soft ... The clefts cause problems with facial muscle development. The origin of macrostomia is not yet fully understood: it could have ...
The location these carnassial pairs is determined primarily by the masseter muscle. In this position, the carnassial teeth ... tendon and muscle. The scissor-like motion is created by the movement between the carnassial pair when the jaw occludes. The ... benefit from most of the force generated by this mastication muscle, allowing for efficient shearing and cutting of flesh, ...
Masseter muscle is compartmentalized by a laminar structure, which was shown to elevate Tnmd mRNA in mouse embryos between ... "Tenomodulin regulated the compartments of embryonic and early postnatal mouse masseter muscle". Annals of Anatomy - ... The epimysium of skeletal muscle is also TNMD -positive. - Tnmd mRNA was detected in eyes, more specifically in the ... In tendinous structures chordae tendineae cordis, which connect papillary muscle to the atrioventricular valves in the heart, ...
Bydyznski T, Stoyva J (1973). "An electromyographic feedback technique for teaching voluntary relaxation of the masseter muscle ... uses surface electrodes to detect muscle action potentials from underlying skeletal muscles that initiate muscle contraction. ... discovering that subjects learned this skill by inhibiting interfering muscles and demonstrating that skeletal muscles are self ... 1962 - Publication of Muscles Alive by John Basmajian and Carlo De Luca 1968 - Annual Veteran's Administration research meeting ...
"Management of Short Face Syndrome with Masseter Muscle Hypertrophy: A Surgery-First Approach". Journal of Maxillofacial and ...
Endo, B (1970). "Analysis of Stresses around the Orbit Due to Masseter and Temporalis Muscles Respectively". The Journal of ... Endo, B (1970). "Analysis of Stresses around the Orbit Due to Masseter and Temporalis Muscles Respectively". The Journal of ... thought to be positively correlated with the size of the masseter muscle, as well as with the improper orientation of bone in ... Anatomy portal Occipitofrontalis muscle Supraciliary scale Frontal sinus This article incorporates text in the public domain ...
The masseter, or cheek muscle, opens and closes the jaw and allows chewing. The Brachiocephalicus is a wide strap-like muscle ... This muscle turns and extends the neck, and makes up the topline if well developed. The Trapezius is a flat, sheet-like muscle ... This muscle moves the head and neck. In ewe-necked or bull-necked horses, this muscle is overdeveloped, and is difficult to get ... This muscle moves the head from side to side, pulls the scapula forward, raises it in collection, and swings the foreleg ...
The fastest reflex recorded in humans happens within the masseter muscle or jaw muscle. The reflex was measured by ... The blink of the eye which is the reflex of the orbicularis oculi muscle was found to have a latency of about 20 to 40 ... motor neurons in the facial motor nucleus or the spinal cord that will directly or indirectly control the movement of muscles. ... electromyography which records the electrical activity during movement of the muscles. This also showed the latency response or ...
The lateral surface is smooth, and affords insertion to the temporalis and masseter muscles. Its medial surface gives insertion ... with the zygomatic arch and masseter removed Coronoid process of mandible Deep dissection of the mandibular nerve and bone ( ... temporo-zygomatic bone and their associated muscles. Most fractures here are caused by strokes (contusion or penetrating ...
... where no extreme specialization of the masseter muscle has evolved. In the protrogomorphous condition, the masseter muscle does ... Likewise, the medial masseter muscle attaches to the base of the zygomatic arch and does not extend to the region in front of ... The skull is protrogomorphous; it has no specialized attachments for the masseter muscles as seen in other rodents. It is ... masticatory muscles, skull shape and digging." Cells Tissues Organs 191.6 (2010): 510-522. Carraway, Leslie N.; Verts, B. J. ( ...
Both the temporalis and masseter muscles are well developed, creating a strong bite force. The teeth are extremely broad and ... Strong muscles are also required for bone crushing, and the temporalis attachment on the skull is enlarged by a strong sagittal ... To feed with this type of structure the fish can protrude its mouth ventrally to permit muscles to be seized by the jaws and ... The sagittal crest projects well above the area of attachment of the neck muscles, and in a large animal it extends back far ...
Masseter muscle - In human anatomy, the masseter is one of the muscles of mastication. Found only in mammals, it is ... Oblique muscle of auricle - The oblique muscle of auricle (oblique auricular muscle or Tod muscle) is an intrinsic muscle of ... The most obvious muscle of mastication is the masseter muscle, since it is the most superficial and one of the strongest. ... "Muscles within muscles: Coordination of 19 muscle segments within three shoulder muscles during isometric motor tasks". J ...
... masseter muscles, and intercostal muscles. Little data exist on the frequency of Trichinella infection in dogs. In Finland, ... Capsule formation in muscle tissue begins about 15 days after infection and is complete after four to eight weeks - the host's ... Once they reach the musculature in the process, they leave the blood vessel and bore into a single muscle fiber. There they ... Larvae can remain infectious in the muscles of a host for years; they are most commonly found in the diaphragm, tongue, ...
It gives attachment throughout nearly the whole of its extent to the masseter muscle. On the inside at the center there is an ... Attached to this is the masseter muscle (related to mastication), the depressor labii inferioris and depressor anguli oris ( ... for the attachment of the masseter laterally, and the medial pterygoid muscle medially; the stylomandibular ligament is ... the inferior muscle of the tongue) attaches; the geniohyoid muscle attaches to the lower mental spine. Above the mental spine, ...
The macroraptorials also had well-developed muscles used in biting-the temporalis and masseter. They also developed buccal ... The elongated lumbar vertebrae of Zygophyseter indicate it had larger multifidus and longissimus back muscles and was, thus, ...
The muscles of mastication (the temporalis muscle, masseter muscle, medial pterygoid muscle and lateral pterygoid muscle) are ... This typically involves the masseter muscle and the anterior portion of the temporalis (the large outer muscles that clench), ... particularly the masseter muscle. Tenderness, pain or fatigue of the muscles of mastication, which may get worse during chewing ... Most (but not all) bruxism includes clenching force provided by masseter and temporalis muscle groups; but some bruxers clench ...
The masseter muscle on the skull was probably the main muscle used for biting down. The later species had a more powerful bite ... The pterygoid muscle in later species was larger to adapt to a grinding motion rather than a cutting motion while chewing. The ... The small neck vertebrae show they had weak neck muscles, as an aquatic creature does not need to hold its head up, and the ... This inclination may have caused less-developed back muscles that would have been needed for high-powered swimming. The ...
It had a large fossa at the insertion of the superficial and deep masseter muscles. Reguero, Marcelo A.; Dozo, María Teresa; ...
It runs forward along the lateral side of the masseter muscle for around 7 cm. In this course, the duct is surrounded by the ... It takes a steep turn at the border of the masseter and passes through the buccinator muscle, opening into the vestibule of the ...
AVE at 10 Hz produced deep masseter muscle relaxation and finger warming within six minutes. Audio entrainment has shown ...
The most obvious muscle of mastication is the masseter muscle, since it is the most superficial and one of the strongest. The ... musculus masseter. The action of the muscle during bilateral contraction of the entire muscle is to elevate the mandible, ... showing the masseter muscle and neighbors. Zygomasseteric system The word masseter (usually /məˈsiːtər/, sometimes /ˈmæsɪtər/) ... The masseter muscle can become enlarged in patients who habitually clench or grind (with bruxism) their teeth and even in those ...
The muscle is shaped similar to a parallelogram, connecting to the mandible (lower jawbone) and the cheekbone. ... The masseter muscle is a facial muscle that plays a major role in the chewing of solid foods. ... The masseter muscle is a facial muscle that plays a major role in the chewing of solid foods. The muscle is shaped similar to a ... The four muscles work together to pull the jaw down and back up again. The masseter is the key muscle that pulls the mandible ...
MRI features characteristic of an intramuscular hemangioma within the masseter muscle.. Hemangioma within the masseter muscle ... A small lobulated soft tissue mass is noted within the right masseter muscle, isointense to the muscle on T1WI, markedly ... Presumptive intramuscular hemangioma of the masseter muscle. (2015) The American journal of case reports. 16: 16-9. doi: ... Haouimi A, Intramuscular hemangioma - masseter muscle. Case study, Radiopaedia.org (Accessed on 24 Apr 2024) https://doi.org/ ...
Background There is an emerging role for the radiological evaluation of the psoas muscle as a marker of sarcopenia, and as a ... This is the first study in a UK elderly trauma population that examines both masseter and psoas muscle groups as indices for ... Uchida Y, Motoyoshi M, Shigeeda T, Shinohara A, Igarashi Y, Sakaguchi M, Shimizu N. Relationship between masseter muscle size ... Uhlich R, Hu P. Sarcopenia diagnosed using masseter muscle area predictive of early mortality following severe traumatic brain ...
Masseter muscle hypertrophy is a unilateral or bilateral enlargement of the masseter muscle, of undefined etiology, which in ... This article describes a case of unilateral masseter muscle hypertrophy, where the surgical resection of the muscle fibers in ... RODRIGUES, Danillo Costa et al. Unilateral Masseter Muscle Hypertrophy: Case Repor. Rev. cir. traumatol. buco-maxilo-fac. [ ... After a two-month follow-up, it was observed that the surgical approach for the treatment of masseter hypertrophy is well ...
Electromyographic analysis of the masseter and temporal muscles in oralized deaf individuals.. Regalo, S C H; Vitti, M; ... This study aimed to assess, by means of computerized bilateral electromyography (EMG), masseter and temporal muscles of 12 ... The analysis made use of Variance Analysis (ANOVA). Significant differences (p < 0.01) for both muscles were found among the ... The stomatognathic system muscles play important roles in functions such as mastication, deglutition, and phonation. ...
It passes through the mandibular notch to reach masseter muscle. It provides motor innervation the masseter muscle, and sensory ... then entering the muscle. The masseteric nerve provides motor innervation the masseter muscle. It additionally sends articular ... the mandibular notch alongside the masseteric artery before branching out upon the surface of the masseter muscle, ... It passes laterally superior to the lateral pterygoid muscle, anterior to the temporomandibular joint, and posterior to the ...
Note the contraction of the masseter and neck muscles. Source: PHIL Photo ID# 2857 ...
... and masseter muscle; anteriorly, by the pterygoid muscles; and posteriorly by the articular tubercle of the temporal bone, ... medially by the superior constrictor muscle, the pharyngobasilar fascia, and the pterygoid plates; laterally by the zygoma, ...
It continues anteroinferiorly, running deep to the tendon of temporalis and the masseter muscles. Once past the masseter muscle ... Course: Runs between the heads of the lateral pterygoid muscle, deep to the masseter, and into the cheek, superficial to the ... It gives off fibers to the skin of the cheek while other fibers dive deep to penetrate the buccinator muscle and reach the ... It conveys general sense fibers from the skin of the cheek and the mucosal lining of the cheek deep to the buccinator muscle. ...
Authors conclude that all procedures showed improvement in symptoms of TrPs in the masseter muscle at 1 and 3 month follow up ... Between 2016 and 2019 patients were included if they were treated with myofascial TPI in masseter muscle. Patients were divided ... Muscle group - a group of muscles that are contiguous and that share a common function, e.g., flexion, stabilization or ... Muscles that are widely separated anatomically and have different functions may be separate muscle groups. ...
Muscle vs disk. : The masseter muscle attaches the skull to the mandible. The disk sits on top of the condylar head in the tmj. ... How are the masseter muscle and the articular disk in jaw distinguished from each other?. ...
Common symptoms of MH include hypercarbia, muscle rigidity, masseter muscle spasm, sinus tachycardia, arrhythmias, hyperthermia ... After 2 hours of resuscitation, the elevated EtCO2 and body temperature began to fall, the muscle rigidity was alleviated, and ... Muscle from patients who are MH-susceptible will show an exaggerated response to these agents. ... The direct cause of MH when it is triggered is uncontrolled release of intracellular calcium from the skeletal muscle ...
On the lateral surface of the ramus are markings for the attachment of the masseter muscle. On the medial surface is the ... Powerful muscles, arising from the temple on either side, attach to the mandible for movements needed in chewing and biting; ... It is in these fossae that the anterior bellies of the digastric muscles are attached. The lowest point of the midline of the ... The important muscles and ligaments that are attached to the mandible are shown in the lower two diagrams. ...
Afferent proprioceptive fibers of V3 from masticatory muscles (masseter, temporalis, medial and lateral pterygoids) pass ... Palpation of the jaw, muscles of mastication, neck, shoulder, and suprahyoid muscles for tenderness suggests temporomandibular ... Efferent innervation supplies muscles of mastication, the tongue, and autonomic reflexes. Below is an overview of the ... The oral cavity is comprised of mucosa, glands, muscle, teeth and sensory receptors. The sensory capabilities of the oral ...
... and in masseter muscles. Abnormalities were also observed in back muscles in 4 patients and in calf muscles in 2 patients. ... Two leg muscle biopsy specimens were obtained from 2 other patients who reported specific muscle pain and had changes ... One tissue sample was from the temporalis muscle of 1 patient, and the other was from the leg muscle of another patient. ... Mild myositis (inflammation) was observed in 3 muscle biopsy specimens examined.. Muscle tissues were ground with sterile glass ...
16 Scopel V, da Costa GS Alves, Urias D. An EMG study of masseter and anterior temporalis muscles in extra-articular myogenous ... 15 Savabi O, Nejatidanesh F, Khosravi S. Effect of occlusal splints on the EMG activities of masseter and temporal muscles ... 3 Ferrario VF et al Immediate effect of a stabilization splint on masticatory muscle activity in TMD patients. J Oral Rehab ... 17 Türp JC, Komine F, Hugger A. Efficacy of stabilization splint therapy for the management of patients with masticatory muscle ...
This patient presented with facial tetany, involving contraction of the masseter and his neck muscles. Tetanus is induced by an ... Tetanus is characterized by painful muscular contractions, primarily of the masseter, and other large muscles. See PHIL 2857, ...
Malignant hyperthermia frequently presents as intractable spasm of the jaw muscles (masseter spasm) which may progress to ... This initially involves consecutively the levator muscles of the face, muscles of the glottis and finally the intercostals and ... Succinylcholine chloride should be employed with caution in patients with fractures or muscle spasm because the initial muscle ... 5.10 Risk of Additional Trauma in Patients With Fractures or Muscle Spasms 5.11 Increase in Intracranial Pressure 5.12 Risk of ...
... rapid movement of the eye in and out of the socket due to flexing of the masseter muscle). No events exceeding a seizure ...
It was found that a subset of trigeminal afferent fibers which innervate the masseter and temporal muscles expressed α, α and α ... may sensitize masticatory muscle nociceptors to increase pain and desensitize muscle proprioceptors to alter muscle tone, ... This study aimed to test whether neck muscle activity can be induced in rats by noxious stimulation of the frontal dura or ... To rule out the possibility that local ischemia was responsible for the observed effect of phenylephrine on masticatory muscle ...
Explore the transformative power of Botox for masseter injections. Enhance your beauty and boost confidence ... Explore the transformative power of Botox for masseter injections. Enhance your beauty and boost confidence ... Simply put, Masseter Botox involves the precise administration of Botox injections into the masseter muscle, a large muscle ... The Role of Masseter Muscle in Facial Structure. The masseter muscle, a key player in the mastication process, also ...
Hi, could any tell me if they have any eye muscle weakness due to ALS?thanks. ... needle EMG exam of right geneoglossus, masseter and orbicularis oris muscles showed normal insertional activity,normal MUPs ... i want to ask you.My father found a muscle itchng on his eyelids and eye sight also became weak. is it happen in mnd what ... However, we have a friend with early als and he is finding that his muscles in his eyelids are weak. I guess that this happens ...
Masseter Muscle. For jaw slimming and to address teeth grinding or TMJ disorders. ... They are used in cosmetic medicine to temporarily paralyze targeted muscles, thereby reducing the appearance of fine lines and ... These treatments temporarily paralyze the underlying muscles responsible for wrinkle formation, which results in a smoother and ... They temporarily paralyze the underlying muscles responsible for wrinkle formation, resulting in smoother skin. ...
However, a significant difference between the two groups was detected in pain pressure threshold of the left masseter muscle, ... Up to three rows of needles were applied to the muscles, spaced at 0.3cm, with up to five needles per row. Treatment was ... Acupuncture with deqi can improve muscle recovery in Bells palsy. Acupuncture that elicits the sensation of deqi can improve ... Somatic tinnitus is defined as tinnitus in which forceful contractions of jaw and neck muscles modulate the psychoacoustic ...
Facial muscles work together to control the parts of your face. They are essential to chewing and making facial expressions. ... 3.0 Beginner is a workout gum for training your facial muscles to get an attractive jawline. ... THE "MASSETER" MUSCLE. *05. WE LOVE SEXY JAWLINES. tone + define your face. *Look your very best - by training your sexiest ... With JAWLINER you can train your sexiest muscle without having to sweat. It is specially designed for facial and jaw muscles ...
This can sometimes be caused by very powerful masseter or jaw muscles. Or it could be caused the repeated use of those muscles ... We use BOTOX® in the masseter muscle, and sometimes in the temporalis muscle to provide relieve from pain and cosmetic ... BOTOX can also be used to relax specific muscles and relieve a number of bruxism-related symptoms and provide significant ...
... the masseter, (b) trapezius, (c) anterior tibialis and (d) flexor carpi ulnaris muscles. This wide applicability is desirable ... of the Laplacian electrode configuration is that EMGs obtained with it are expected to be sensitive to the firing of the muscle ... a) Masseter, (b) trapezius, (c) anterior tibialis, and (d) flexor carpi ulnaris muscles. ... a) Masseter, (b) trapezius, (c) anterior tibialis, and (d) flexor carpi ulnaris muscles. ...
This week Im getting masseter muscle Botox to relax my jaw and allow the muscle to reduce, which should help with my clenching ...
  • Along with the other three muscles of mastication (temporalis, medial pterygoid, and lateral pterygoid), the masseter is innervated by the anterior division of the mandibular division (V3) of the trigeminal nerve. (wikipedia.org)
  • The masseteric nerve is a branch of (the anterior division of) the mandibular nerve (CN V3) (itself a branch of the trigeminal nerve (CN V)). It passes laterally superior to the lateral pterygoid muscle, anterior to the temporomandibular joint, and posterior to the tendon of the temporalis muscle. (wikipedia.org)
  • The muscle paralysis effect is how a Botox shot reduces the crinkling and wrinkling that naturally happens when we make certain expressions (and simply, aging). (healthline.com)
  • It is a botox procedure applied to the masseter chewing muscle and temporal. (drorhanaydin.com)
  • Common Botox treatment areas include the frown lines, forehead wrinkles, crows feet, masseter jawline slimming, puckered chin, bunny lines and neck wrinkles. (ceruleanmedical.com)
  • Botox is also used to slim the face by treating hypertrophied masseter muscles resulting in a better balanced face and enhanced jawline. (ceruleanmedical.com)
  • Your cosmetic specialist will inject the Botox gently and precisely into the wrinkle-causing muscles, temporarily relaxing facial muscles, preventing the formation of new wrinkles and softening existing lines.nnWith repeated treatments your muscles become re-trained, limiting the damage incurred by the skin's natural collagen and reducing the development of new lines and wrinkles. (ceruleanmedical.com)
  • Carefully placed injections using BOTOX or Dysport temporarily paralyze the muscles responsible for these wrinkles, allowing the skin to smooth and soften for a rejuvenated appearance. (chicagoaesthetics.com)
  • Botox & Dysport work by relaxing the muscles and preventing those muscles from contracting, so they don't react when you smile, laugh or frown. (chicagoaesthetics.com)
  • Botox in the masseters can be used to slim the face and help create the upside-down triangle that everyone wants. (chicagoaesthetics.com)
  • To relieve teeth grinding, a qualified medical aesthetics professional can expertly inject Botox directly into your frontal and masseter muscles. (mrcbc.com)
  • Botox for teeth grinding also has an added cosmetic bonus of gradually reducing the size of your masseter muscles, which can give you a slimmer overall look and a more streamlined jawline. (mrcbc.com)
  • Botox treatment is an injectable fine line muscle relaxer. (shobhitaesthetics.com)
  • Botox helps block signals from the nerves to the muscles and the infused muscle is unable to contract to make wrinkles relax and soften them. (shobhitaesthetics.com)
  • Botox is derived from Botulinum toxin A, a neurotoxin that can temporarily relax certain treated muscles. (nwface.com)
  • The masseter parallels the medial pterygoid muscle, but it is stronger and superficial fibres can cause protrusion. (wikipedia.org)
  • Deaf individuals showed a lower muscular activity for clinical activities that demanded a greater masseter and temporal muscular activity such as mastication , mouth opening and closing, and dental compression. (bvsalud.org)
  • Tetanus is characterized by painful muscular contractions, primarily of the masseter, and other large muscles. (cdc.gov)
  • Weakness of intercostal and diaphragmatic and improving the quality of life in Duchenne muscular muscles with spinal deformity affects respiratory dystrophy children. (who.int)
  • Even if the hypertrophy is bilateral, asymmetry of the face may still occur due to unequal enlargement of the muscles. (wikipedia.org)
  • Masseter muscle hypertrophy is a unilateral or bilateral enlargement of the masseter muscle, of undefined etiology, which in most cases generates an aesthetic discomfort, and in some cases a functional one as well. (bvsalud.org)
  • This article describes a case of unilateral masseter muscle hypertrophy, where the surgical resection of the muscle fibers in an intraoral approach and a osteotomy with a reciprocating saw were performed in the mandibular angle region. (bvsalud.org)
  • After a two-month follow-up, it was observed that the surgical approach for the treatment of masseter hypertrophy is well advised, since the aesthetic results are excellent, with similarity to the contralateral side of mandibular angle. (bvsalud.org)
  • The present study is about management 8 years old male child with B/L lower limb weakness and calf muscle hypertrophy.etc, so according to Ayurvedic management with Panchkarma procedures and internal medicines given the case was managed. (who.int)
  • The action of the muscle during bilateral contraction of the entire muscle is to elevate the mandible, raising the lower jaw. (wikipedia.org)
  • This patient presented with facial tetany, involving contraction of the masseter and his neck muscles. (cdc.gov)
  • Lower motor neurons transmit impulses to the neuromuscular junction to initiate muscle contraction. (msdmanuals.com)
  • This study aimed to assess, by means of computerized bilateral electromyography (EMG), masseter and temporal muscles of 12 oralized deaf individuals in clinical activities that involve part of this masticatory musculature and compare this system's functionality with that of 12 normal listening individuals, performing the same activities. (bvsalud.org)
  • Horizontal MRI scan of a head, at the level of the mandibular teeth, showing the masseter muscle and neighbors. (wikipedia.org)
  • The surgical approach involves intervetions performed in either the compromised muscle or the mandibular angle bone structure, or in both. (bvsalud.org)
  • It passes through the mandibular notch to reach masseter muscle. (wikipedia.org)
  • It crosses (the posterior portion of) the mandibular notch alongside the masseteric artery before branching out upon the surface of the masseter muscle, then entering the muscle. (wikipedia.org)
  • In human anatomy, the masseter is one of the muscles of mastication. (wikipedia.org)
  • The most obvious muscle of mastication is the masseter muscle, since it is the most superficial and one of the strongest. (wikipedia.org)
  • The stomatognathic system muscles play important roles in functions such as mastication , deglutition , and phonation . (bvsalud.org)
  • All 8 patients showed changes in muscles of mastication, including superficial temporalis and deep temporalis, and in masseter muscles. (cdc.gov)
  • It is the motor nerve for the muscles of mastication and contains proprioceptive fibers. (medscape.com)
  • The mesencephalic nucleus is in the midbrain and receives proprioceptive fibers from all muscles of mastication. (medscape.com)
  • The proprioceptive fibers of CN V arise from the muscles of mastication and the extraocular muscles. (medscape.com)
  • The motor nucleus of CN V receives cortical fibers for voluntary control of the muscles of mastication. (medscape.com)
  • Finally, the muscle undergoes spasm with malignant hyperthermia as do other skeletal muscles, but this one is easily noted, since it is on the face. (wikipedia.org)
  • In a 1995 report, Cheney describes harvesting the midportion of the temporalis muscle, then tightly suturing the residual muscle fascia to close the defect. (medscape.com)
  • A biopsy specimen was obtained from the temporalis muscle of 1 of these patients. (cdc.gov)
  • The masseter muscle can become enlarged in patients who habitually clench or grind (with bruxism) their teeth and even in those who constantly chew gum. (wikipedia.org)
  • The frozen muscles cannot habitually clench and contract as they normally would, meaning less pain and discomfort for you. (mrcbc.com)
  • Dissection, showing salivary glands of right side (Masseter visible at center) Left temporal bone, outer surface Left temporal bone, inferior surface Left zygomatic bone, temporal surface Mandible, outer surface, side view The arteries of the face and scalp. (wikipedia.org)
  • Electromyographic analysis of the masseter and temporal muscles in oralized deaf individuals. (bvsalud.org)
  • This will result in muscle release and an eventually dramatic improvement on frown lines formed between the eyebrows, crow's feet at the eyes corner, forehead lines, and lines around your lips. (chicagoaesthetics.com)
  • Weakness of specific muscle groups can cause disorders of eye movement, dysarthria, dysphagia, or respiratory weakness. (msdmanuals.com)
  • These treatments work by momentarily obstructing nerve signals and also muscle contractions in the areas where they're injected. (collagenrestore.net)
  • because with each of them there is a difference in the amplitude of the movements of the diaphragm, in the breathing pauses and in the degree of tension of the intercostal muscles (located in the anterior and lateral part of the thorax). (lorecentral.org)
  • Singers often experience various kinds of masseter tension, which is often treated with transdermal massages or stretches as a vocal warm-up. (wikipedia.org)
  • Strong emphasis is placed on learning the facial muscles and proper injection depths to ensure great results. (aesthetic.education)
  • This is largely controlled by the nasalis muscle which wraps over your nose. (nwface.com)
  • It is not meant to relax the entire nasalis muscle, only the portions causing bunny lines. (nwface.com)
  • The coronoid head of the masseter's tendon and muscle fibers run posterolaterally from the coronoid process of the mandible towards the posterior third of the zygomatic arch. (wikipedia.org)
  • The use of muscle transfer is particularly useful with atrophy of the mimetic muscles and/or facial fat. (medscape.com)
  • with time, muscles atrophy. (msdmanuals.com)
  • The masseteric nerve provides motor innervation the masseter muscle. (wikipedia.org)
  • Several different regional transfers have been described, but the masseteric and temporalis transfers remain the workhorses in muscle transfer techniques. (medscape.com)
  • The masseteric transfer provides reanimation of the lower face with separate muscle slips sutured to the upper lip, oral commissure, and lower lip. (medscape.com)
  • With minimal pain and no downtime, your muscles are temporarily frozen for a period of three to four months. (mrcbc.com)
  • Abnormalities were also observed in back muscles in 4 patients and in calf muscles in 2 patients. (cdc.gov)
  • In The Physiology of Joints, Volume III , French surgeon and anatomist Adalbert I. Kapandji states that for every inch the head goes forward it gains an additional ten pounds of weight in terms of strain on the posterior neck and upper back muscles. (sinewchannels.com)
  • With a head-forward posture, this balanced support is disrupted, and the posterior neck and upper back muscles then become increasingly more overloaded (and painful) with every additional degree of head-forward posture. (sinewchannels.com)
  • With the head an inch forward (neutral is considered as consisting of the ear aligning over the acromion process which is the highest point of the shoulder) this means that the posterior neck and upper back muscles have to support about 20 pounds of weight all day. (sinewchannels.com)
  • As stated above, for every inch the head moves forward, it gains an additional 10 pounds of weight in terms of strain on the posterior neck and upper back muscles. (sinewchannels.com)
  • It also includes a mode to tighten the jawline, lift the cheeks, and reduce the masseter muscles. (beautyandsales.com)
  • It provides motor innervation the masseter muscle, and sensory innervation to the temporomandibular joint. (wikipedia.org)
  • Depending on the thickness of the muscles 40-60 units of injections are given to change the shape of the jaw. (shobhitaesthetics.com)
  • Malignant hyperthermia (MH) is a rare, inherited disorder of skeletal muscle that presents as a hypermetabolic response triggered by halogenated anesthetics, succinylcholine, or both. (medscape.com)
  • MH is an inherited disorder of skeletal muscle that classically presents itself as a hypermetabolic response to halogenated anesthetic agents, succinylcholine, or both. (medscape.com)
  • The direct cause of MH when it is triggered is uncontrolled release of intracellular calcium from the skeletal muscle sarcoplasmic reticulum. (medscape.com)
  • The deep head of the muscle is partly concealed, anteriorly, by the superficial portion. (wikipedia.org)
  • The mimetic muscles direct facial movements. (medscape.com)
  • Dynamic wrinkles are caused by repeated muscle movements and develop over time with your natural aging process. (chicagoaesthetics.com)
  • Static is formed when the tissues are constantly relaxed, and frequent muscle movements cause dynamic. (chicagoaesthetics.com)
  • The Facial Coding System (FACS) and Action Units (AUs) study how facial muscle movements influence the expression of an emotion. (lorecentral.org)
  • Place the fingers of each hand over the muscle and ask the patient to clench his or her teeth several times. (wikipedia.org)
  • However, no other signs are present except those involved in changes in occlusion intraorally such as pain, and the enlargement corresponds with the outline of the muscle. (wikipedia.org)
  • Investigation by using magnetic resonance imaging (MRI) was prompted by development of visible swelling of the face in 9 patients and swelling of the calf muscles in 4 patients. (cdc.gov)
  • Waddling gait, Grower sign and Calf muscle pseudohyertrophy are classical findings. (who.int)
  • What this means is that the muscles of the posterior cervical spine are working overtime, day in and day out, and for a prolonged time. (sinewchannels.com)
  • In each procedure, the muscle is divided into slips and is attached to the submucosa or subdermis. (medscape.com)
  • Under the control of the seventh cranial nerve (CN VII), the movement of these muscles correlates with the communication of human thought, emotion, and expression. (medscape.com)
  • Several techniques have evolved to correct these deficits, including dynamic techniques such as nerve grafting and muscle transposition, and static techniques with fascial or alloplastic slings. (medscape.com)
  • Rehabilitation of the facial nerve and subsequent reinnervation of the mimetic muscles is achieved. (medscape.com)
  • When targeted to a specific area, neuromodulators will block the nerve stimulation to its muscles. (chicagoaesthetics.com)
  • They might additionally reduce the formation of new wrinkles or fold lines by avoiding the tightening of some face muscle mass. (collagenrestore.net)
  • Occasionally, the levator labii superioris-the muscle responsible for causing a gummy smile-is sometimes involved in bunny line formation. (nwface.com)
  • Myofascial pain involves discomfort or pain in the muscles that control jaw function. (yourptm.com)
  • The masseter muscle's positioning is a distinguishing feature of hystricognathous creatures such as mole-rats, where it passes partially through the infraorbital foramen and connects to the bone on the opposite side. (wikipedia.org)
  • When necessary, your dentist or physician can prescribe stronger pain or anti-inflammatory medications, muscle relaxants, or anti-depressants to help ease symptoms. (yourptm.com)
  • 1,500 limb muscle biopsy specimens in the past 20 years for various muscle diseases at the University of Malaya Medical Centre did not yield any sarcocyst-positive tissues (K.T. Wong, unpub. (cdc.gov)
  • genetic testing, muscle biopsy and muscle imaging. (who.int)
  • Some people have other health problems that co-exist with TMJ disorders, such as chronic fatigue syndrome, sleep disturbances or fibromyalgia, a painful condition that affects muscles and other soft tissues throughout the body. (yourptm.com)
  • Temporomandibular Dysfunction (TMD) is a set of disorders in- volving the masticatory muscles in the TMJ and associated structures. (bvsalud.org)
  • Weakness may affect a few or many muscles and develop suddenly or gradually. (msdmanuals.com)
  • Weakness is loss of muscle strength, although many patients also use the term when they feel generally fatigued or have functional limitations (eg, due to pain or limited joint motion) even though muscle strength is normal. (msdmanuals.com)
  • Peripheral polyneuropathies tend to be most noticeable in the longest nerves (ie, weakness is more prominent in the distal limb than the proximal and in legs more than arms) and produce signs of lower motor neuron dysfunction (eg, decreased reflexes and muscle tone). (msdmanuals.com)
  • Myasthenia Gravis Myasthenia gravis is characterized by episodic muscle weakness and easy fatigability caused by autoantibody- and cell-mediated destruction of acetylcholine receptors. (msdmanuals.com)
  • Accepted: 24-01-2023 weakness of a selective group of muscles without involvement of nervous system. (who.int)
  • Therapeutic Exercise: Your therapist may instruct you on various exercises and stretches that you can do at home to help improve your posture and stretch the muscles that may be causing your jaw pain. (yourptm.com)
  • However, sometimes all three of these muscles can become spasmed, making it very difficult to turn the neck in any direction without considerable pain. (sinewchannels.com)
  • And it is not just the muscles which are involved with neck pain from a head-forward posture. (sinewchannels.com)
  • Upper motor neuron dysfunction disinhibits lower motor neurons, resulting in increased muscle tone (spasticity) and increased muscle stretch reflexes (hyperreflexia). (msdmanuals.com)
  • The Sarcocystis nesbitti 18S rRNA gene and sarcocysts were obtained from muscle tissues of 2 students. (cdc.gov)
  • known and most have been isolated from muscle tissues of various intermediate hosts, including mammals, birds, and reptiles. (cdc.gov)
  • The average weight of the head is about 4.5-5 kg (10-11 pounds) and, in a balanced posture, it is supported evenly amid the muscles of the neck. (sinewchannels.com)
  • The scalp defect after temporalis harvest can be corrected with an implant placed at the time of muscle transposition. (medscape.com)
  • It utilizes OnabotulinumtoxinA, to deaden muscle for a brief time. (shobhitaesthetics.com)
  • Scale) and improvement in muscle function. (bvsalud.org)

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