Neck Muscles: 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).Neck: The part of a human or animal body connecting the HEAD to the rest of the body.Muscles: Contractile tissue that produces movement in animals.Head Movements: Voluntary or involuntary motion of head that may be relative to or independent of body; includes animals and humans.Neck Pain: Discomfort or more intense forms of pain that are localized to the cervical region. This term generally refers to pain in the posterior or lateral regions of the neck.Head and Neck Neoplasms: Soft tissue tumors or cancer arising from the mucosal surfaces of the LIP; oral cavity; PHARYNX; LARYNX; and cervical esophagus. Other sites included are the NOSE and PARANASAL SINUSES; SALIVARY GLANDS; THYROID GLAND and PARATHYROID GLANDS; and MELANOMA and non-melanoma skin cancers of the head and neck. (from Holland et al., Cancer Medicine, 4th ed, p1651)Electromyography: Recording of the changes in electric potential of muscle by means of surface or needle electrodes.Head: The upper part of the human body, or the front or upper part of the body of an animal, typically separated from the rest of the body by a neck, and containing the brain, mouth, and sense organs.Torticollis: A symptom, not a disease, of a twisted neck. In most instances, the head is tipped toward one side and the chin rotated toward the other. The involuntary muscle contractions in the neck region of patients with torticollis can be due to congenital defects, trauma, inflammation, tumors, and neurological or other factors.Muscle, Skeletal: 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.Muscle Proteins: The protein constituents of muscle, the major ones being ACTINS and MYOSINS. More than a dozen accessory proteins exist including TROPONIN; TROPOMYOSIN; and DYSTROPHIN.Muscle, Smooth: 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)Muscle Contraction: 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.Facial Muscles: 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)Muscle Fibers, Skeletal: 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.Muscle, Smooth, Vascular: The nonstriated involuntary muscle tissue of blood vessels.Vibration: A continuing periodic change in displacement with respect to a fixed reference. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Labyrinth Diseases: Pathological processes of the inner ear (LABYRINTH) which contains the essential apparatus of hearing (COCHLEA) and balance (SEMICIRCULAR CANALS).Proprioception: Sensory functions that transduce stimuli received by proprioceptive receptors in joints, tendons, muscles, and the INNER EAR into neural impulses to be transmitted to the CENTRAL NERVOUS SYSTEM. Proprioception provides sense of stationary positions and movements of one's body parts, and is important in maintaining KINESTHESIA and POSTURAL BALANCE.Acceleration: An increase in the rate of speed.Mastoid: The posterior part of the temporal bone. It is a projection of the petrous bone.Muscle Development: 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.Posture: The position or attitude of the body.Occipital Bone: Part of the back and base of the CRANIUM that encloses the FORAMEN MAGNUM.Isometric Contraction: Muscular contractions characterized by increase in tension without change in length.Whiplash Injuries: Hyperextension injury to the neck, often the result of being struck from behind by a fast-moving vehicle, in an automobile accident. (From Segen, The Dictionary of Modern Medicine, 1992)Tegmentum Mesencephali: Portion of midbrain situated under the dorsal TECTUM MESENCEPHALI. The two ventrolateral cylindrical masses or peduncles are large nerve fiber bundles providing a tract of passage between the FOREBRAIN with the HINDBRAIN. Ventral MIDBRAIN also contains three colorful structures: the GRAY MATTER (PERIAQUEDUCTAL GRAY), the black substance (SUBSTANTIA NIGRA), and the RED NUCLEUS.Muscle Fatigue: 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.Muscle Fibers, Fast-Twitch: 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.Muscle Denervation: The resection or removal of the innervation of a muscle or muscle tissue.Fixation, Ocular: The positioning and accommodation of eyes that allows the image to be brought into place on the FOVEA CENTRALIS of each eye.Muscle Fibers, Slow-Twitch: 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.Anti-Dyskinesia Agents: Drugs used in the treatment of movement disorders. Most of these act centrally on dopaminergic or cholinergic systems. Among the most important clinically are those used for the treatment of Parkinson disease (ANTIPARKINSON AGENTS) and those for the tardive dyskinesias.Electric Stimulation: Use of electric potential or currents to elicit biological responses.Cervical Vertebrae: The first seven VERTEBRAE of the SPINAL COLUMN, which correspond to the VERTEBRAE of the NECK.Myocytes, Smooth Muscle: Non-striated, elongated, spindle-shaped cells found lining the digestive tract, uterus, and blood vessels. They are derived from specialized myoblasts (MYOBLASTS, SMOOTH MUSCLE).Mitochondria, Muscle: Mitochondria of skeletal and smooth muscle. It does not include myocardial mitochondria for which MITOCHONDRIA, HEART is available.Motor Neurons: Neurons which activate MUSCLE CELLS.Vestibule, Labyrinth: An oval, bony chamber of the inner ear, part of the bony labyrinth. It is continuous with bony COCHLEA anteriorly, and SEMICIRCULAR CANALS posteriorly. The vestibule contains two communicating sacs (utricle and saccule) of the balancing apparatus. The oval window on its lateral wall is occupied by the base of the STAPES of the MIDDLE EAR.Movement: The act, process, or result of passing from one place or position to another. It differs from LOCOMOTION in that locomotion is restricted to the passing of the whole body from one place to another, while movement encompasses both locomotion but also a change of the position of the whole body or any of its parts. Movement may be used with reference to humans, vertebrate and invertebrate animals, and microorganisms. Differentiate also from MOTOR ACTIVITY, movement associated with behavior.Biomechanical Phenomena: The properties, processes, and behavior of biological systems under the action of mechanical forces.Oculomotor Muscles: The muscles that move the eye. Included in this group are the medial rectus, lateral rectus, superior rectus, inferior rectus, inferior oblique, superior oblique, musculus orbitalis, and levator palpebrae superioris.Neck Injuries: General or unspecified injuries to the neck. It includes injuries to the skin, muscles, and other soft tissues of the neck.Muscle, Striated: One of two types of muscle in the body, characterized by the array of bands observed under microscope. Striated muscles can be divided into two subtypes: the CARDIAC MUSCLE and the SKELETAL MUSCLE.Orientation: Awareness of oneself in relation to time, place and person.Muscle Spindles: 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.Muscle Relaxation: That phase of a muscle twitch during which a muscle returns to a resting position.Cats: The domestic cat, Felis catus, of the carnivore family FELIDAE, comprising over 30 different breeds. The domestic cat is descended primarily from the wild cat of Africa and extreme southwestern Asia. Though probably present in towns in Palestine as long ago as 7000 years, actual domestication occurred in Egypt about 4000 years ago. (From Walker's Mammals of the World, 6th ed, p801)Time Factors: Elements of limited time intervals, contributing to particular results or situations.Psychomotor Performance: The coordination of a sensory or ideational (cognitive) process and a motor activity.Muscle Weakness: A vague complaint of debility, fatigue, or exhaustion attributable to weakness of various muscles. The weakness can be characterized as subacute or chronic, often progressive, and is a manifestation of many muscle and neuromuscular diseases. (From Wyngaarden et al., Cecil Textbook of Medicine, 19th ed, p2251)Respiratory Muscles: These include the muscles of the DIAPHRAGM and the INTERCOSTAL MUSCLES.Papillary Muscles: Conical muscular projections from the walls of the cardiac ventricles, attached to the cusps of the atrioventricular valves by the chordae tendineae.Superior Colliculi: The anterior pair of the quadrigeminal bodies which coordinate the general behavioral orienting responses to visual stimuli, such as whole-body turning, and reaching.Rotation: Motion of an object in which either one or more points on a line are fixed. It is also the motion of a particle about a fixed point. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)