| musculus mylohyoideus | <anatomy> Pertaining to, or in the region of, the lower jaw and the hyoid apparatus; as, the mylohyoid nerve. <anatomy, muscle> Origin, mylohyoid line of mandible; insertion, upper border of hyoid bone and raphe separating muscle from its fellow; action, elevates floor of mouth and the tongue, depresses jaw when hyoid is fixed; nerve supply, nerve to mylohyoid from mandibular division of trigeminal. Synonym: musculus mylohyoideus, mylohyoideus. Origin: Gr. The molar teeth + E. Hyoid. (05 Mar 2000) |
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| musculus mylopharyngeus | See: superior constrictor muscle of pharynx. (05 Mar 2000) |
| musculus nasalis | <anatomy> Compound muscle consisting of: a transverse part (pars transversa musculi nasalis, musculus compressor naris) arising from the maxilla above the root of the canine tooth on each side and forming an aponeurosis across the bridge of the nose; and an alar part (pars alaris musculi nasalis, musculus dilator naris) arising from the maxilla above the lateral incisor and attaching to the wing of the nose; the alar part dilates the nostril; nerve supply, facial. Synonym: musculus nasalis, nasal muscle. (05 Mar 2000) |
| musculus obturator externus | <anatomy, muscle> Origin, lower half of margin of obturator foramen and adjacent part of external surface of obturator membrane; insertion, trochanteric fossa of greater trochanter; action, rotates thigh laterally; nerve supply, obturator. Synonym: musculus obturator externus, external obturator muscle. (05 Mar 2000) |
| musculus obturator internus | <anatomy, muscle> Origin, pelvic surface of obturator membrane and margin of obturator foramen; insertion, passes out of pelvis through lesser sciatic foramen, in so doing, making a 90 |
| musculus occipitalis | See: occipitofrontalis muscle. (05 Mar 2000) |
| musculus occipitofrontalis | <anatomy> It is a part of musculus epicranius; the occipital belly (occipitalis muscle) arises from the occipital bone and inserts into the galea aponeurotica; the frontal belly (frontalis muscle) arises from the galea and inserts into the skin of the eyebrow and nose; action, to move the scalp; nerve supply, facial. Synonym: musculus occipitofrontalis, occipitofrontal muscle. (05 Mar 2000) |
| musculus omohyoideus | <anatomy> Formed of two bellies attached to intermediate tendon; origin, by inferior belly from upper border of scapula between superior angle and notch; insertion, by superior belly into hyoid bone; action, depresses hyoid; nerve supply, upper cervical spinal nerves through ansa cervicalis. Synonym: musculus omohyoideus, omohyoid. (05 Mar 2000) |
| musculus opponens digiti minimi | <anatomy, muscle> Origin, hamulus of the hamate bone and transverse carpal ligament; insertion, shaft of fifth metacarpal; action, "cups" palm, drawing ulnar side of hand toward centre of palm; nerve supply, ulnar. Synonym: musculus opponens digiti minimi, musculus opponens digiti quinti, musculus opponens minimi digiti, opposer muscle of little finger. (05 Mar 2000) |
| musculus opponens digiti quinti | <anatomy, muscle> Origin, hamulus of the hamate bone and transverse carpal ligament; insertion, shaft of fifth metacarpal; action, "cups" palm, drawing ulnar side of hand toward centre of palm; nerve supply, ulnar. Synonym: musculus opponens digiti minimi, musculus opponens digiti quinti, musculus opponens minimi digiti, opposer muscle of little finger. (05 Mar 2000) |
| musculus opponens minimi digiti | <anatomy, muscle> Origin, hamulus of the hamate bone and transverse carpal ligament; insertion, shaft of fifth metacarpal; action, "cups" palm, drawing ulnar side of hand toward centre of palm; nerve supply, ulnar. Synonym: musculus opponens digiti minimi, musculus opponens digiti quinti, musculus opponens minimi digiti, opposer muscle of little finger. (05 Mar 2000) |
| musculus opponens pollicis | <anatomy, muscle> Origin, ridge of trapezium and flexor retinaculum; insertion, anterior surface of the full length of the shaft of the first metacarpal bone; action, acts at carpometacarpal joint to "cup" palm, enabling one to oppose thumb to other fingers; nerve supply, median. Synonym: musculus opponens pollicis, opposer muscle of thumb. (05 Mar 2000) |
| musculus orbicularis | <anatomy> A sphincter-like sheet of muscle that encircles an orifice such as the mouth or the palpebral fissures. Synonym: musculus orbicularis, orbicular muscle, orbicularis. (05 Mar 2000) |
| musculus orbicularis oculi | <anatomy> Consists of three portions: orbital part, or external portion, which arises from frontal process of maxilla and nasal process of frontal bone, encircles aperture of orbit, and is inserted near origin; palpebral part, or internal portion, which arises from medial palpebral ligament, passes through each eyelid, and is inserted into lateral palpebral raphe; lacrimal part (tensor tarsi muscle, Duverney's or Horner's muscle) arises from posterior lacrimal crest and passes across lacrimal sac to join palpebral portion; action, closes eye, wrinkles forehead vertically; nerve supply, facial. Synonym: musculus orbicularis oculi, musculus orbicularis palpebrarum, orbicular muscle of eye, sphincter oculi. (05 Mar 2000) |
| musculus orbicularis oris | <anatomy, muscle> Origin, by nasolabial band from septum of the nose, by superior incisive bundle from incisor fossa of maxilla, by inferior incisive bundle from lower jaw each side of symphysis; insertion, fibres surround mouth between skin and mucous membrane of lips and cheeks, and are blended with other muscles; action, closes lips; nerve supply, facial. Synonym: musculus orbicularis oris, musculus sphincter oris, orbicular muscle of mouth, sphincter oris. (05 Mar 2000) |