muscles definition

A large group of muscles in the front of the abdomen that assists in the regular breathing movement and supports the muscles of the spine while lifting and keeping abdominal organs such as the intestines in place. Abdominal muscles play a key role in exercises such as sit-ups.

(12 Dec 1998)

The fluid remaining after the coagulation of muscle plasma and the separation of myosin.

(05 Mar 2000)

Striated muscles having fibres connected at either or both extremities with the bony framework of the body. These are found in appendicular and axial muscles.

(12 Dec 1998)

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 fibres are bound together into sheets or bundles by reticular fibres and frequently elastic nets are also abundant.

(12 Dec 1998)

The nonstriated, involuntary muscle tissue of blood vessels.

(12 Dec 1998)

Muscles forming the wall of the abdomen including rectus abdominis, external and internal oblique muscles, transversus abdominis, and quadratus abdominis.

Synonyms: musculi abdominis.

(05 Mar 2000)

The musculus stapedius and musculus tensor tympani.

Synonyms: musculi ossiculorum auditus.

(05 Mar 2000)

The muscles of the coccyx considered as a group, including the musculus coccygeus and the inconstant ventral and dorsal sacrococcygeal muscles.

Synonyms: musculi coccygei.

(05 Mar 2000)

Preferred term: extraocular muscles

The numerous muscles supplied by the facial nerve that are attached to and move the skin of the face. Nomina Anatomica also includes the buccinator muscle in this group; even though it functions primarily in mastication.

Synonyms: musculi faciales, facial muscles, mimetic muscles.

(05 Mar 2000)

The muscles of expression, of mastication, and the suboccipital muscles in general.

Synonyms: musculi capitis.

(05 Mar 2000)

The intrinsic muscles that regulate the length, position and tension of the vocal cords and adjust the size of the openings between the aryepiglottic folds, the ventricular folds and the vocal folds.

Synonyms: musculi laryngis.

(05 Mar 2000)

Muscles derived from the first (mandibular) arch used in chewing; all receive innervation from the motor root of the trigeminal nerve via its mandibular division.

See: masseter muscle, temporalis muscle, lateral pterygoid muscle, medial pterygoid muscle.

(05 Mar 2000)

The anterolateral muscles of the neck including the platysma, sternocleidomastoid, suprahyoid muscles, infrahyoid muscles, longus colli and scalene muscles.

Synonyms: musculi colli.

(05 Mar 2000)

The muscles of the back in general, including those attaching the shoulder girdle to the trunk posteriorly, the posterior serratus muscles, and the erector spinae.

Synonyms: musculi dorsi, dorsal muscles.

(05 Mar 2000)

The muscles attaching to the rib cage including the pectoral muscles, serratus anterior, subclavius, levator muscles, intercostal muscles, transverse thoracic muscle, subcostal muscles, and diaphragm.

Synonyms: musculi thoracis.

(05 Mar 2000)

The extrinsic muscles include the genioglossus, hyoglossus, chondroglossus, and styloglossus muscles; the intrinsic muscles are the vertical, transverse, and the superior and inferior longitudinal; all are innervated by the hypoglssal nerve.

Synonyms: musculi linguae.

(05 Mar 2000)

A fine murmur heard on auscultation over the belly of a contracting muscle.

(05 Mar 2000)

<physiology> Painful involuntary muscle contractions. Often seen in skeletal muscle after acute injury (muscle strain).

(07 Apr 1998)

A combination of the symptoms of increased resistance to lengthening, hyperactive tendon reflexes, and clonus. Muscle spasticity occurs in hemiplegia.

(12 Dec 1998)

A specialised muscle fibre found in tetrapod vertebrates. A bundle of muscle fibres is innervated by sensory neurones. Stretching the muscle causes the neurones to fire, the muscle spindle thus functions as a stretch receptor.

This entry appears with permission from the Dictionary of Cell and Molecular Biology

(11 Mar 2008)

Mechanoreceptors found between skeletal muscle fibres. Muscle spindles are arranged in parallel with muscle fibres and respond to the passive stretch of the muscle, but cease to discharge if the muscle contracts isotonically, thus signaling muscle length. The muscle spindles are the receptors responsible for the stretch or myotactic reflex (reflex, stretch).

(12 Dec 1998)

An acute tearing injury to muscle. Usually associated with a small amount of bleeding (haematoma) into the injured muscle tissue.

(27 Sep 1997)