Pterygoid Muscles
Masticatory Muscles
Temporomandibular Joint
Temporal Muscle
Temporomandibular Joint Dysfunction Syndrome
Mandible
Mandibular Nerve
Sphenoid Bone
EMG activities of two heads of the human lateral pterygoid muscle in relation to mandibular condyle movement and biting force. (1/45)
Electromyographic (EMG) activities of the superior (SUP) and inferior heads (INF) of the lateral pterygoid muscle (LPT) were recorded in humans during voluntary stepwise changes in biting force and jaw position that were adopted to exclude the effects of acceleration and velocity of jaw movements on the muscle activity. The SUP behaved like a jaw-closing muscle and showed characteristic activity in relation to the biting force. It showed a considerable amount of background activity (5-32% of the maximum) even in the intercuspal position without teeth clenching and reached a nearly maximum activity at relatively lower biting-force levels than the jaw-closing muscles during increment of the biting force. Stretch reflexes were found in the SUP, the function of which could be to stabilize the condyle against the biting force that pulls the condyle posteriorly. This notion was verified by examining the biomechanics on the temporomandibular joint. The complex movements of the mandibular condyle in a sagittal plane were decomposed into displacement in the anteroposterior direction (Ac) and angle of rotation (RAc) around a kinesiological specific point on the condyle. In relation to Ac, each head of the LPT showed quite a similar behavior to each other in all types of jaw movements across all subjects. Working ranges of the muscle activities were almost constant (Ac <3 mm for the SUP and Ac >3 mm for the INF). The amount of EMG activity of the SUP changed in inverse proportion to Ac showing a hyperbola-like relation, whereas that of the INF changed rather linearly. The EMG amplitude of the SUP showed a quasilinear inverse relation with RAc in the hinge movement during which the condyle rotated with no movement in the anteroposterior direction. This finding suggests that the SUP controls the angular relationship between the articular disk and the condyle. On the other hand, the position of the disk in relation to the maxilla, not to the condyle, is controlled indirectly by the INF because the disk is attached to the condyle by tendinous ligaments. (+info)The pterygopalatine fossa: postoperative MR imaging appearance. (2/45)
BACKGROUND AND PURPOSE: The pterygopalatine fossa (PPF) is an important anatomic location of the deep portion of the face. It is essential to review this area on both pre- and posttreatment studies of head and neck malignancies to assess local extent of disease or recurrence and perineural tumor spread. The purpose of this study was to review the postoperative appearance of the PPF on MR images. METHODS: Imaging and clinical data of 10 patients who underwent surgical resection of tumor in which the PPF was violated at surgery were reviewed. Patients were included in the study if there was no imaging or clinical evidence of tumor in the PPF pre- or postoperatively. Postoperative MR studies were examined to assess the appearance of the PPF. RESULTS: The PPF is consistently and persistently abnormal after surgical violation. There is loss of the normal T1 signal hyperintensity and abnormal, increased contrast enhancement, as seen on fat-suppressed T1-weighted images. These postoperative changes are strikingly similar to those of tumor involvement. CONCLUSION: After surgical violation, the PPF will always appear abnormal on MR images, and the expected imaging findings must be recognized to avoid the misdiagnosis of tumor recurrence. (+info)Positional relationships between the masticatory muscles and their innervating nerves with special reference to the lateral pterygoid and the midmedial and discotemporal muscle bundles of temporalis. (3/45)
For an accurate assessment of jaw movement, it is crucial to understand the comprehensive formation of the masticatory muscles with special reference to the relationship to the disc of the temporomandibular joint. Detailed dissection was performed on 26 head halves of 14 Japanese cadavers in order to obtain precise anatomical information of the positional relationships between the masticatory muscles and the branches of the mandibular nerve. After complete removal of the bony elements, the midmedial muscle bundle in all specimens and the discotemporal muscle bundle in 6 specimens, derivatives of the temporalis, which insert into the disc were observed. On the anterior area of the articular capsule and the disc of the temporomandibular joint, the upper head of the lateral pterygoid, the midmedial muscle bundle of temporalis and the discotemporal bundle of temporalis were attached mediolaterally, and in 3 specimens the posterosuperior margin of the zygomaticomandibularis was attached to the anterolateral area of the disc. It is suggested that these muscles and muscle bundles contribute to various mandibular movements. Although various patterns of the positional relationships between the muscles and muscle bundles and the their innervating nerves are observed in the present study, relative positional relationships of the muscles and muscle bundles and of nerves of the mandibular nerve are consistent. A possible scheme of the developmental formation of the masticatory muscles based on the findings of the positional relationships between the muscles and the nerves is presented. (+info)Cortical bone mineral density in asymmetrical mandibles: a three-dimensional quantitative computed tomography study. (4/45)
The three-dimensional distribution (3D) of the highest mineralized cortical bone was evaluated in 32 subjects between the ages of 8 and 30 years with asymmetrical mandibles using quantitative computed tomography (QCT). The geometrical distribution of the highest mineralized areas (> 1250 mg/cm3) representative of mandibular cortical bone was determined by 3D reconstruction of the images. The length of the mandible on each side was determined by defining a new linear measurement from the centre of the 3D reconstructed condyle to the midline of the symphysis as identified from a submental view. The cross-sectional areas of the masseter and medial pterygoid muscles were assessed from bilateral axial views through the middle of the muscles parallel to the Frankfort-Horizontal plane. Comparison between the lengths of the two mandibular sides (right-left = mm) indicated a range of asymmetries with an equal number of subjects with the left and right mandible longer. Comparison of the area of highest mineralized cortical bone between the right and left sides (R/L) to the ratio of the mandibular length (R/L) showed a high correlation coefficient (r = 0.629) suggesting that the shortest mandibular side had more highly mineralized bone. A comparison of the area of highest mineralized cortical bone between the right and left sides (R/L) to the ratio of cross-sectional areas of the muscles showed the highest correlation coefficient (r = 0.724) with the ipsilateral masseter muscle. These findings indicate that asymmetrical mandibles are associated with asymmetrical distributions of the highest mineralized cortical bone and that this is age dependent. (+info)Functional properties of single motor units in inferior head of human lateral pterygoid muscle: task relations and thresholds. (5/45)
The aim of this study was to clarify the normal function of the inferior head of the human lateral pterygoid muscle (IHLP). The hypothesis was that an important function of the IHLP is in the fine control of horizontal jaw movements. The activities of 99 single motor units (SMUs) were recorded from IHLP (22 recordings from 16 subjects). Most recording sites were identified by computer tomography (CT). All 99 SMUs were active during contralateral jaw movements with the teeth apart, and protrusive jaw movements with the teeth apart, and 81% (48 of 59 units studied during all 3 tasks) were active during submaximal jaw-opening movements. None were active on maximal ipsilateral or retrusive jaw movements with the teeth apart nor on jaw closing/clenching in intercuspal position; nor were they spontaneously active when the jaw was at the clinically determined postural jaw position. Thresholds of SMUs ranged from <0.2 mm of contralateral or protrusive horizontal displacements to 61-89% of the maximum contralateral or protrusive displacement, respectively. For the 35 units continuously active during the contralateral task, 23 (66%) were recruited within 2 mm of contralateral displacement [25 (63% of 40 units) for protrusion]. Recruitment thresholds (mm) of some of the units were rate dependent with thresholds significantly decreasing with increasing rate of horizontal jaw movement in protrusion and contralateral movements. At eight recording sites where up to six SMUs were able to be discriminated, the average thresholds of successively recruited SMUs were within a 1-mm increment of horizontal jaw displacement. After dividing IHLP into four regions, the SMUs recorded in the superior-medial zone exhibited significantly lower mean threshold values than for the SMUs recorded in the other zones (no units were recorded in the inferior-lateral zone). This provides suggestive evidence supporting previously proposed notions of functional heterogeneity within IHLP. Taken together, the data suggest that specific regions of the IHLP are capable of selective activation in a finely controlled manner to allow the application of the appropriate force vector (magnitude and direction) to effect the required condylar movement needed for the generation and control of horizontal jaw movements. (+info)Functional properties of single motor units in the inferior head of human lateral pterygoid muscle: task firing rates. (6/45)
The precise function of the inferior head of the human lateral pterygoid muscle (IHLP) is unclear. The aim of this study was to clarify the normal function of the IHLP. The hypothesis was that an important function of the IHLP is the generation and fine control of horizontal (i.e., anteroposterior and mediolateral) jaw movements. The activities of 50 single motor units (SMUs) were recorded from IHLP (14 subjects) during two- or three-step contralateral movement (n = 36) and/or protrusion (n = 33). Most recording sites were identified by computer tomography. There was a statistically significant overall increase in firing rate as the magnitude of jaw displacement increased between the holding phases (range of increments: 0.3-1.6 mm). The firing rates during the dynamic phases for each unit were significantly greater than those during the previous holding phases but less than those during the subsequent holding phases. For the contralateral step task at the intermediate rate, the cross-correlation coefficients between jaw displacement in the mediolateral axis and the mean firing rate of each unit ranged from r = 0.29 to 0.77; mean +/- SD; r = 0.49 +/- 0.13 (protrusive step task: r = 0.12-0.74, r = 0.44 +/- 0.14 for correlation with anterior-posterior axis). The correlation coefficients at the fast rate during the contralateral step task and the protrusive step task were significantly higher than those at the slow rate. The firing rate change of the SMUs per unit displacement between holding phases was significantly greater for the lower-threshold than for the higher-threshold units during contralateral movement and protrusion. After dividing IHLP into four regions, the SMUs recorded in the superior part exhibited significantly greater mean firing rate changes per unit displacement during protrusion than for the SMUs recorded in the inferior part. Significantly fewer units were related to the protrusive task in the superior-medial part. These data support previously proposed notions of functional heterogeneity within IHLP. The present findings provide further evidence for an involvement of the IHLP in the generation and fine control of horizontal jaw movements. (+info)Somatostatin immunoreactivity in quail pterygopalatine ganglion. (7/45)
In the ciliary ganglion of the chicken and quail, somatostatin (SOM) is an exclusive marker for parasympathetic postganglionic neurons innervating the choroid. A second parasympathetic pathway projecting to the choroid originates from the pterygopalatine ganglion. The aim of this study was to investigate SOM immunoreactivity in the pterygopalatine ganglion of the Japanese quail (Coturnix coturnix japonica) and on neurons within the choroid, the intrinsic choroidal neurons (ICN). We did so using immunohistochemistry and subsequent light, electron and confocal laser scanning microscopy. Pterygopalatine neurons were characterized by nNOS-immunohistochemistry or NADPH-diaphorase cytochemistry. SOM immunoreactivity was absent in the perikarya, but neurons were densely surrounded by SOM-positive nerve fibres. Electron microscopy revealed that these fibres formed contacts with and without membrane specializations on pterygopalatine neurons. In the choroid, neuronal nitric-oxide synthase (nNOS)-immunoreactive ICN were likewise closely apposed by SOM-immunoreactive nerve fibres, as revealed by confocal microscopy. There was no detectable co-localization of the markers. In the absence of tracing studies, it is open to speculation whether SOM immunoreactivity originates from preganglionic fibres of the superior salivatory nucleus, postganglionic fibres of the ciliary ganglion or fibres of the brainstem via as yet unknown pathways. SOM may regulate the production of NO in pterygopalatine neurons and ICN, respectively, and is therefore involved in neuronal circuits regulating ocular homeostasis. (+info)Modeling elastic properties in finite-element analysis: how much precision is needed to produce an accurate model? (8/45)
The influence of elastic properties on finite-element analysis was investigated using a finite-element model of a Macaca fascicularis skull. Four finite-element analyses were performed in which the model was assigned different sets of elastic properties. In analysis 1, elastic properties were modeled isotropically using published data obtained from human limb bones. Analyses 2-4 used data obtained from skulls of a closely allied species, M. mulatta, but varied as to how those data were incorporated into the model. In analysis 2, the model was assigned a single set of isotropic elastic properties. In analysis 3, each region within the model was assigned its own set of isotropic elastic properties. Finally, in analysis 4, each region received its own set of orthotropic elastic properties. Although a qualitative assessment indicates that the locations of strain concentrations across the model are broadly similar in all analyses, a quantitative assessment of strain indicates some differences between the analyses. When strain data from the finite-element analyses were compared to strain data derived from in vivo experiments, it was found that the model deformed most realistically using the orthotropic elastic properties employed in analysis 4. Results suggest that finite-element analyses can be adversely affected when elastic properties are modeled imprecisely, and that modelers should attempt to obtain elastic properties data about the species and skeletal elements that are the subjects of their analyses. (+info)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.
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 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 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.
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.
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.
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.
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.
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.
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.
The sphenoid bone is a complex, irregularly shaped bone located in the middle cranial fossa and forms part of the base of the skull. It articulates with several other bones, including the frontal, parietal, temporal, ethmoid, palatine, and zygomatic bones. The sphenoid bone has two main parts: the body and the wings.
The body of the sphenoid bone is roughly cuboid in shape and contains several important structures, such as the sella turcica, which houses the pituitary gland, and the sphenoid sinuses, which are air-filled cavities within the bone. The greater wings of the sphenoid bone extend laterally from the body and form part of the skull's lateral walls. They contain the superior orbital fissure, through which important nerves and blood vessels pass between the cranial cavity and the orbit of the eye.
The lesser wings of the sphenoid bone are thin, blade-like structures that extend anteriorly from the body and form part of the floor of the anterior cranial fossa. They contain the optic canal, which transmits the optic nerve and ophthalmic artery between the brain and the orbit of the eye.
Overall, the sphenoid bone plays a crucial role in protecting several important structures within the skull, including the pituitary gland, optic nerves, and ophthalmic arteries.
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.
Pterygoid muscle
Could Your Lateral Pterygoid Muscle Be Causing TMJ Pain? | Colgate®
Medial Pterygoid - Stretching - Learn Muscles
Lateral Pterygoid Muscle: It's Relevance to Clinical Dentistry - Occlusion Connections
IRUCAA@TDC : Desmin and nerve terminal expression during embryonic development of the lateral pterygoid muscle in mice
Electromyography assisted application of botulinum toxin in pterygoid musculature for the treatment of masticatory myofascial...
Malignant Tonsil Tumor Surgery: Practice Essentials, History Of The Procedure, Problem
Vaccine Therapy in Treating Patients With Stage IV Head and Neck Cancer
Interactive Prenatal Development Timeline - Advanced
The Radiology Assistant : Trigeminal neuralgia
Masticatory Muscle Pain and Disorders | SpringerLink
Bassett Collection - Lane Medical Library - Stanford University School of Medicine
Refinement Database | Animal Welfare Institute
Use of Buccal Fat Pad in the Treatment of Peri-Implant Mucosal Defect: A Case Report | Journal of Oral Implantology
Neurotree - Shivani Ruparel
I Didn't Know Chiropractic Could Treat That! - Foot Levelers
TMD Treatment | Evaluate Options and Correct TMJ Disorder
TMJ Syndrome-Jaw Pain and Clicking is Not Normal - Los Angeles, West Hollywood, Beverly Hills Chiropractor Dr. Nick Campos
A method for morphological feature extraction based on variational auto-encoder : an application to mandible shape | bioRxiv
Posted on the Gab Board about name suggestions for my cookie business if anyone would like to help