Makindo Medical Notes"One small step for man, one large step for makindo" |
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Muscles of the Head and Neck - Listed Alphabetically | ||||||
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Muscle | Origin | Insertion | Action | Innervation | Artery | Notes |
anterior scalene | anterior tubercles of the transverse processes of vertebrae C3-C6 | scalene tubercle of the first rib | elevates the first rib; flexes and laterally bends the neck | brachial plexus, C5-C7 | ascending cervical a., a branch of the thyrocervical trunk | a muscle of inspiration; an important landmark of the neck; it is located between the subclavian vein and the subclavian artery; the roots of the brachial plexus pass posterior to it; the phrenic nerve crosses its anterior surface (Greek, scalene = uneven) |
aryepiglottic | apex (superior part) of the arytenoid cartilage | epiglottis | draws the epiglottis posteriorly and downward during swallowing | inferior laryngeal nerve, from recurrent laryngeal nerve, a branch of the of vagus (X) | laryngeal br. of the superior thyroid a. | the mucosa is raised by the underlying aryepiglottic m. to form the aryepiglottic fold |
arytenoid, oblique | muscular process of the arytenoid cartilage | posterior surface of the contralateral arytenoid cartilage, near its apex | draws arytenoid cartilages together, adducting the vocal folds | inferior laryngeal nerve, from recurrent laryngeal nerve, a branch of the of vagus (X) | laryngeal br. of the superior thyroid a. | the oblique arytenoid m. lies posterior to the transverse arytenoid m.; the arytenoideus is often considered to be one muscle with oblique and transverse fibers ( |
arytenoid, transverse | posterior surface of the arytenoid cartilage | posterior surface of the contralateral arytenoid cartilage | draws arytenoid cartilages together, adducting the vocal folds | inferior laryngeal nerve, from recurrent laryngeal nerve, a branch of the vagus nerve (X) | laryngeal br. of the superior thyroid a. | the transverse arytenoid m.lies anterior to the oblique arytenoid m.; the arytenoideus is often considered to be one muscle with oblique and transverse parts |
auricular | anterior: galea aponeurotica anterior to ear; superior: galea aponeurotica superior to ear; posterior: mastoid process | auricle anteriorly, superiorly and posteriorly | wiggle the ears | anterior & superior: temporal branches of facial nerve (VII); posterior: posterior auricular branch of facial nerve (VII) | superficial temporal a., posterior auricular a. | the auricular muscles are derived from the mesenchyme of the second pharyngeal arch, as are the muscles of facial expression |
buccinator | pterygomandibular raphe, mandible, and the maxilla lateral to the molar teeth | angle of mouth and the lateral portion of the upper and lower lips | pulls the corner of mouth laterally; presses the cheek against the teeth | buccal branches of the facial nerve (VII) | facial a. | although the buccinator is important in mastication, it is innervated by the buccal branch of the facial nerve and NOT by the buccal nerve from V3 (a sensory nerve) (Latin, buccinator = trumpeter) |
chondroglossus | medial side of the lesser horn and body of the hyoid bone | ascends to blend with the intrinsic tongue musculature | pulls the sides of the tongue down | hypoglossal nerve (XII) | lingual a. | chondroglossus is often considered to be part of the hyoglossus muscle |
ciliary | meridional fibers: scleral spur; circular fibers: encircle the ciliary process | meridional fibers: ciliary process; circular fibers: encircle the ciliary process | relaxes the suspensory ligament of the lens | parasympathetic fibers in the oculomotor nerve (III), synapsing in the ciliary ganglion | ophthalmic a. | relaxation of the suspensory ligament allows the lens to thicken for accommodation (near vision) |
constrictor, inferior pharyngeal | oblique line of the thyroid cartilage, lateral surface of cricoid cartilage | midline pharyngeal raphe | constricts pharyngeal cavity | vagus (X), via the pharyngeal plexus, with aid from the superior laryngeal and recurrent laryngeal nerves | ascending pharyngeal a., superior thyroid a., inferior thyroid a. | the most external of the three pharyngeal constructor mm. |
constrictor, middle pharyngeal | lesser and greater horns of the hyoid bone and the inferior part of the stylohyoid ligament | midline pharyngeal raphe | constricts the pharyngeal cavity | vagus (X), via the pharyngeal plexus | ascending pharyngeal a. | of the three pharyngeal constrictors, this one is intermediate in both superior/inferior position and depth |
constrictor, superior pharyngeal | medial pterygoid plate, pterygoid hamulus, pterygomandibular raphe, mylohyoid line of mandible | pharyngeal tubercle and midline pharyngeal raphe | constricts the pharyngeal cavity | vagus (X), via the pharyngeal plexus | ascending pharyngeal a. | the most internal of the three pharyngeal constructor mm. |
corrugator | medial part of the supercillary arch | skin of the medial half of the eyebrow | pulls eyebrows together medially | temporal branch of the facial nerve (VII) | supratrochlear a. | this muscle causes the furrowed brow of the worried look (Latin, corrugator= to wrinkle) |
cricoarytenoid, lateral | arch of the cricoid cartilage | muscular process of the arytenoid cartilage | draws the muscular process of the arytenoid cartilage anteriorly, which pivots the arytenoid cartilage and adducts the vocal folds | inferior laryngeal nerve, from the recurrent laryngeal nerve, a branch of the vagus nerve (X) | superior laryngeal a., cricothyroid branch of the superior thyroid a. | an antagonist of the posterior cricoarytenoid m.; the arteries that supply the larynx anastomose within the larynx to supply the mucous membranes and muscles |
cricoarytenoid, posterior | posterior surface of the lamina of the cricoid cartilage | muscular process of the arytenoid cartilage | draws the muscular process posteriorly, which pivots the arytenoid cartilage and abducts the vocal folds | inferior laryngeal nerve, from the recurrent laryngeal nerve, a branch of the vagus nerve (X) | superior laryngeal a., cricothyroid branch of the superior thyroid a. | the posterior cricoarytenoid is the only ABductor of the vocal folds; the arteries that supply the larynx anastomose within the larynx to supply the mucous membranes and muscles |
cricopharyngeus | lateral surface of the cricoid cartilage | midline pharyngeal raphe | constricts the pharyngeal cavity and the entrance to the oesophagus | recurrent laryngeal nerve, a branch of the vagus nerve (X) | cricothyroid branch of the superior thyroid a., ascending pharyngeal a. | cricopharyngeus represents the lowest fibers of the inferior pharyngeal constrictor; it is continuous with the oesophagus below and marks the beginning of it |
cricothyroid | arch of the cricoid cartilage | inferior border of the thyroid cartilage | draws the thyroid cartilage forward, lengthening the vocal ligaments | external branch of superior laryngeal nerve, a branch of the vagus nerve (X) | cricothyroid branch of the superior thyroid a. | this is the only intrinsic muscle of the larynx that is not supplied by the recurrent laryngeal n.; ALL other laryngeal muscles are innervated by recurrent laryngeal nerve, via its inferior laryngeal branch |
depressor anguli oris | oblique line of the mandible | angle of the mouth | pulls the corner of the mouth downward | marginal mandibular & buccal branches of the facial nerve (VII) | inferior labial branch of the facial a., mental a. | a "frown" muscle |
depressor labii inferioris | anterior surface of the mandible | skin of the lower lip | depresses the lower lip | marginal mandibular branch of the facial nerve (VII) | inferior labial branch of the facial a., mental a. | this muscle is used to bare the lower incisor teeth |
depressor septi | maxilla near the midline above the incisor teeth | nasal septum | depresses the nasal septum; involved in flaring the nostrils | buccal branch of facial nerve (VII) | superior labial branch of the facial a. | depressor septi is considered a part of the nasalis m. |
digastric | anterior belly: digastric fossa of the mandible; posterior belly: mastoid notch of the temporal bone | body of the hyoid via a fibrous loop over an intermediate tendon | elevates the hyoid bone; depresses the mandible | anterior belly: mylohyoid nerve, from the mandibular division of the trigeminal nerve (V); posterior belly: facial nerve (VII) | anterior belly: submental a.; posterior belly: occipital a. | the digastric m. forms two sides of the submandibular triangle; it is formed from mesenchyme derived from the first two pharyngeal arches, hence its dual innervation |
dilator pupillae | outer margin of iris | inner margin of iris | dilates the pupil | sympathetic fibers via short ciliary nerves, synapsing in superior cervical sympathetic ganglion | ophthalmic a. | none |
epicranius | frontalis: galea aponeurotica; occipitalis: superior nuchal line | frontalis: skin of the eyebrows; occipitalis: galea aponeurotica | elevates the eyebrows and wrinkles the forehead | frontalis: temporal branches of the facial nerve (VII); occipitalis: posterior auricular branch of the facial nerve (VII) |
frontalis: supraorbital and supratrochlear aa.; occipitalis: occipital a. |
the frontalis and occipitalis muscles are two bellies of the epicranius muscle; also known as: occipitofrontalis m. |
frontalis | galea aponeurotica | skin of the eyebrow | elevates the eyebrows and wrinkles the forehead | temporal branches of the facial nerve (VII) | supraorbital and supratrochlear aa. | frontalis is the anterior belly of the epicranius muscle |
genioglossus | mental spine on the inner aspect of the mental symphysis | fans out to insert into the tongue from the tip to the base | protrudes the tongue (inferior fibers); depresses tongue (middle fibers) | hypoglossal nerve (XII) | lingual a. | an extrinsic muscle of the tongue; XII innervates all tongue muscles except palatoglossus [innervated by vagus (X), as are most of the palate and pharynx muscles]; genioglossus is used to test the function of cranial nerve XII |
geniohyoid | mental spines of the mandible | body of the hyoid bone | elevates the hyoid bone; depresses the mandible | ventral primary ramus of spinal nerve C1 via fibers carried by the hypoglossal nerve | lingual a., submental a. | thyrohyoid and geniohyoid receive ansa cervicalis fibers that travel with the hypoglossal nerve distal to the superior limb of the ansa cervicalis |
hyoglossus | upper border of the greater horn of the hyoid and body of the hyoid bone | spreads out into the intrinsic muscles of the tongue | depresses the sides of the tongue; retracts the tongue | hypoglossal nerve (XII) | lingual a. | an extrinsic muscle of the tongue |
inferior oblique | floor of the orbit lateral to the lacrimal groove | sclera on the inferior surface of the eyeball | elevates and abducts the corneal part of the eye; rotates the superior pole of the iris laterally; when the eye is adducted, this muscle elevates the cornea | oculomotor nerve (III), inferior division | ophthalmic a. | clinicians examining the eye will ask the patient to look toward the bridge of the nose to test the function of this muscle |
inferior pharyngeal constrictor | oblique line of the thyroid cartilage, lateral surface of cricoid cartilage | midline pharyngeal raphe | constricts pharyngeal cavity | vagus (X), via the pharyngeal plexus, with aid from the superior laryngeal and recurrent laryngeal nerves | ascending pharyngeal a., superior thyroid a., inferior thyroid a. | the most external of the three pharyngeal constructor mm. |
inferior rectus | common tendinous ring at the apex of the orbit | sclera on the inferior surface of the eyeball | depresses and adducts the corneal part of the eyeball; rotates the superior pole of the iris laterally | oculomotor nerve (III), inferior division | ophthalmic a. | because this muscle approaches the eyeball from a medial direction, it has a rotational action on the iris |
lateral cricoarytenoid | arch of the cricoid cartilage | muscular process of the arytenoid cartilage | draws the muscular process of the arytenoid cartilage anteriorly, which pivots the arytenoid cartilage and adducts the vocal folds | inferior laryngeal nerve, from the recurrent laryngeal nerve, a branch of the vagus nerve (X) | superior laryngeal a., cricothyroid branch of the superior thyroid a. | an antagonist of the posterior cricoarytenoid m.; the arteries that supply the larynx anastomose within the larynx to supply the mucous membranes and muscles |
lateral pterygoid | superior head: greater wing of the sphenoid bone; inferior head: lateral surface of the lateral pterygoid plate | superior head: capsule and & articular disk of the temporomandibular joint; inferior head: neck of the mandible | protracts the mandible; opens the mouth; active in grinding actions of chewing | lateral pterygoid branch of the mandibular division of the trigeminal nerve (V) | pterygoid branch of the maxillary a. | the only one of the muscles of mastication that opens the mouth; the superior head of lateral pterygoid is sometimes called sphenomeniscus due to its insertion into the disc of the temporomandibular joint (Greek, pterygoid = wing-shaped) |
lateral rectus | common tendinous ring at the apex of the orbit | sclera on the lateral surface of the eyeball | abducts the corneal part of the eyeball | abducens nerve (VI) | ophthalmic a. | loss of function of the abducens nerve will cause the eye to be abducted |
levator anguli oris | canine fossa of the maxilla | angle (corner) of the mouth | elevates the angle of the mouth | buccal branch of the facial nerve (VII) | infraorbital a., superior labial branch of the facial a. | a "smile" muscle |
levator labii superioris | inferior margin of the orbit | skin of the upper lip | elevates the upper lip | buccal branch of the facial nerve (VII) | infraorbital a., superior labial branch of the facial a. | levator labii superioris is used to bare the upper incisor teeth, as in a sneer (Latin, levator = to lift + labial = lips) |
levator labii superioris alaque nasi | frontal process of the maxilla | ala of the nose and skin of the upper lip | elevates the upper lip and flares the nostril | buccal branch of the facial nerve (VII) | infraorbital a., superior labial branch of the facial a. | (Latin, levator = to lift + labial = lips) |
levator palpebrae superioris | apex of the orbit above the optic canal | skin and fascia of upper eyelid and the superior tarsal plate | elevates the upper eyelid | oculomotor nerve (III) and sympathetics (to the superior tarsal portion) | ophthalmic a. | fibers inserting into the superior tarsal plate are called superior tarsal muscle and are smooth muscle; lesion of the sympathetic supply causes slight ptosis (drooping of the eyelid) (Latin, levator = to lift + palpebrae = eyelid) |
levator scapulae | transverse processes of C1-4 vertebrae | medial border of the scapula from the superior angle to the spine | elevates scapula | dorsal scapular nerve (C5); the upper part of the muscle receives branches of C3 & C4 spinal nerves | dorsal scapular a. | named for its action (Latin, levator = to lift) |
levator veli palatini | apex of the petrous part of the temporal bone and the medial surface of the auditory tube cartilage | muscles and fascia of the soft palate; palatine aponeurosis | elevates the soft palate | vagus nerve (X) via the pharyngeal plexus | ascending pharyngeal a. | a derivative of the fourth pharyngeal arch (Latin, levator = to lift) |
linguae, longitudinalis | within tongue | within tongue near the apex | shapes the tongue for speech and mastication | hypoglossal nerve (XII) | lingual a. | an intrinsic muscle of the tongue; longitudinalis has superior and inferior subdivisions that span the length of the tongue |
linguae, transversus | within tongue | within tongue | compresses the sides of the tongue; shapes the tongue for speech and mastication | hypoglossal nerve (XII) | lingual a. | an intrinsic muscle of the tongue whose fibers run transversely |
linguae, verticalis | within tongue | within tongue | shapes the tongue for speech and mastication | hypoglossal nerve (XII) | lingual a. | an intrinsic muscle of the tongue whose fibers run superoinferiorly |
longus capitis | anterior tubercles of vertebrae C3-6 | basilar portion of the occipital bone | flex the head and neck | cervical plexus, ventral primary rami of spinal nerves C1-4 | deep cervical a. | none |
longus colli | anterior tubercles and anterior surfaces of the bodies of vertebrae C3-T3 | anterior arch of atlas, anterior tubercles of C5-6, anterior surfaces of bodies of vertebrae C2-4 | flex neck, rotate and laterally bend neck | cervical and brachial plexus, C2-7 | deep cervical a. | none |
masseter | zygomatic arch and zygomatic bone | lateral surface of the ramus and angle of the mandible | elevates the mandible | nerve to the masseter, from the mandibular division of the trigeminal nerve (V) | masseteric branch of the maxillary a. | (Greek, masseter = the chewer) |
medial pterygoid | medial surface of the lateral pterygoid plate, pyramidal process of the palatine bone, tuberosity of the maxilla | medial surface of the ramus and angle of the mandible | elevates and protracts the mandible | medial pterygoid branch of the mandibular division of the trigeminal nerve (V) | pterygoid branch of the maxillary a. | this muscle mirrors the masseter m. in position and action with the ramus of the mandible between the two mm. (Greek, pterygoid = wing-shaped) |
medial rectus | common tendinous ring at the apex of the orbit | sclera on the medial surface of the eyeball | adducts the corneal part of the eyeball | oculomotor nerve (III) (inferior division) | ophthalmic a. | this muscle directly opposes the action of the lateral rectus m. |
mentalis | anterior surface of the mandible near the mental symphysis (midline) | skin of the chin | elevates the lower lip and skin of chin | marginal mandibular branch of the facial nerve (VII) | mental a., inferior labial branch of the facial a. | |
middle pharyngeal constrictor | lesser and greater horns of the hyoid bone and the inferior part of the stylohyoid ligament | midline pharyngeal raphe | constricts the pharyngeal cavity | vagus (X), via the pharyngeal plexus | ascending pharyngeal a. | of the three pharyngeal constrictors, this one is intermediate in both superior/inferior position and depth |
middle scalene | posterior tubercles of the transverse processes of vertebrae C2-C7 | upper surface of the first rib behind the subclavian artery | elevates the first rib; flexes and laterally bends the neck | brachial plexus, C3-C8 | ascending cervical a. | a muscle of respiration (inspiratory); also called scalenus medius; penetrated by the dorsal scapular n. and long thoracic n. (Greek, scalene = uneven) |
musculus uvulae | posterior nasal spine | mucosa of the uvula | shortens the uvula | vagus nerve (X) via pharyngeal plexus | lesser palatine a. | the soft palate and uvula resist the upward pressure of the tongue during swallowing |
mylohyoid | mylohyoid line of mandible | midline raphe and body of the hyoid bone | elevates the hyoid bone and the tongue; depresses the mandible | mylohyoid nerve from the inferior alveolar nerve, a branch of the mandibular division of the trigeminal nerve (V) | mylohyoid branch of the inferior alveolar a. | the nerve to mylohyoid also innervates the anterior belly of digastric m.; both muscles are derivatives of the second pharygneal arch |
nasalis | maxilla above the incisor teeth and the canine teeth | ala of the nose and midline aponeurosis | flattens the nose, flare the nostrils | buccal branch of the facial nerve (VII) | superior labial branch of the facial a. | nasalis has two subsidiary parts: nasalis pars alaris and pars transversa |
nasalis pars alaris | maxilla above the canine teeth | ala of the nose | flares the nostrils | buccal branch of facial nerve (VII) | superior labial branch of the facial a. | a subdivision of the nasalis m. (Latin, pars = a part) |
nasalis pars transversa | maxilla above the incisor teeth | midline aponeurosis | flattens the nose | buccal branch of facial nerve (VII) | superior labial branch of the facial a. | a subdivision of the nasalis m. (Latin, pars = a part) |
oblique arytenoid | muscular process of the arytenoid cartilage | posterior surface of the contralateral arytenoid cartilage, near its apex | draws arytenoid cartilages together, adducting the vocal folds | inferior laryngeal nerve, from recurrent laryngeal nerve, a branch of the of vagus (X) | laryngeal br. of the superior thyroid a. | the oblique arytenoid m. lies posterior to the transverse arytenoid m.; the arytenoideus is often considered to be one muscle with oblique and transverse fibers |
oblique, inferior | floor of the orbit lateral to the lacrimal groove | sclera on the inferior surface of the eyeball | elevates and abducts the corneal part of the eye; rotates the superior pole of the iris laterally; when the eye is adducted, this muscle elevates the cornea | oculomotor nerve (III), inferior division | ophthalmic a. | clinicians examining the eye will ask the patient to look toward the bridge of the nose to test the function of this muscle |
oblique, superior | apex of the orbit above the optic canal | sclera on the posterior superior surface of the eyeball | depresses and abducts the eyeball; rotates the superior pole of the iris medially | trochlear nerve (IV) | ophthalmic a. | passes through a fibrocartilagenous pulley known as the trochlea; when the eye is adducted, this muscle moves the cornea inferiorly |
occipitalis | superior nuchal line | galea aponeurotica | pulls the scalp posteriorly; elevates the eyebrows | posterior auricular branch of the facial nerve (VII) | occipital a. | occipitalis is the posterior belly of the epicranius muscle |
occipitofrontalis | frontalis: galea aponeurotica; occipitalis: superior nuchal line | frontalis: skin of the eyebrows; occipitalis: galea aponeurotica | elevates the eyebrows and wrinkles the forehead | frontalis: temporal branches of the facial nerve (VII); occipitalis: posterior auricular branch of the facial nerve (VII) |
frontalis: supraorbital and supratrochlear aa.; occipitalis: occipital a. |
the frontalis and occipitalis muscles are two bellies of the occipitofrontalis muscle; also known as: epicranius m. |
omohyoid | inferior belly: upper border of the scapula medial to the scapular notch; superior belly: intermediate tendon | inferior belly: intermediate tendon; superior belly: lower border of the hyoid bone lateral to the sternohyoid insertion | depresses/stabilizes the hyoid bone | ansa cervicalis | transverse cervical a. | the intermediate tendon of omohyoid is tethered to the clavicle by a fascial sling |
orbicularis oculi | orbital part: medial orbital margin and the medial palpebral ligament; palpebral part: medial palpebral ligament | orbital part: skin of the lateral cheek; palpebral part: lateral palpebral raphe | closes the eyelids | temporal & zygomatic branches of the facial nerve (VII) | supraorbital a., supratrochlear a., infraorbital a., angular branch of the facial a. | activated involuntarily in the blink reflex; the palpebral part is active in normal blinking and the orbital part is used to forcefully close the eye |
orbicularis oris | skin and fascia of lips and the area surrounding the lips | skin and fascia of the lips | purses the lips | buccal branch of the facial nerve (VII) | superior and inferior labial branches of the facial a., mental a., infraorbital a. | the "kissing" muscle |
palatoglossus | palatine aponeurosis | side of the tongue, entering it from above | elevates and retracts the tongue | vagus nerve (X) via the pharyngeal plexus | tonsilar branch of the facial a., ascending pharyngeal a. | although palatoglossus sounds like a tongue muscle (and would therefore be innervated by XII), it is a palatal muscle innervated by X |
palatopharyngeus | posterior margin of the bony palate and the palatine aponeurosis | posterior wall of the pharynx and the posterior margin of the thyroid cartilage | elevates the larynx | vagus nerve (X) via pharyngeal plexus | ascending pharyngeal a. | palatopharyngeus is part of the inner longitudinal muscle layer of the pharynx |
platysma | fascia overlying the pectoralis major and deltoid muscles | inferior border of the mandible and skin of lower face | draws the corners of the mouth down; it aids in depression of the mandible | cervical branch of the facial nerve (VII) | facial a. | platysma is derived from the mesenchyme of the second pharyngeal arch (Greek, platysma = a flat plate) |
posterior cricoarytenoid | posterior surface of the lamina of the cricoid cartilage | muscular process of the arytenoid cartilage | draws the muscular process posteriorly, which pivots the arytenoid cartilage and abducts the vocal folds | inferior laryngeal nerve, from the recurrent laryngeal nerve, a branch of the vagus nerve (X) | superior laryngeal a., cricothyroid branch of the superior thyroid a. | the posterior cricoarytenoid is the only ABductor of the vocal folds; the arteries that supply the larynx anastomose within the larynx to supply the mucous membranes and muscles |
posterior scalene | posterior tubercles of the transverse processes of vertebrae C5-C7 | lateral surface of the second rib | elevates the second rib; flexes and laterally bends the neck | brachial plexus, C7-C8 | ascending cervical a. | a muscle of respiration (inspiratory); it is the longest of the scalene muscles (Greek, scalene = uneven) |
procerus | nasal bone | skin between the eyebrows | depresses the medial corners of the eyebrows | temporal branch of the facial nerve (VII) | supratrochlear a. | (Latin, procerus = long and streched out) |
pterygoid, lateral | superior head: greater wing of the sphenoid bone; inferior head: lateral surface of the lateral pterygoid plate | superior head: capsule and & articular disk of the temporomandibular joint; inferior head: neck of the mandible | protracts the mandible; opens the mouth; active in grinding actions of chewing | lateral pterygoid branch of the mandibular division of the trigeminal nerve (V) | pterygoid branch of the maxillary a. | the only one of the muscles of mastication that opens the mouth; the superior head of lateral pterygoid is sometimes called sphenomeniscus due to its insertion into the disc of the temporomandibular joint (Greek, pterygoid = wing-shaped) |
pterygoid, medial | medial surface of the lateral pterygoid plate, pyramidal process of the palatine bone, tuberosity of the maxilla | medial surface of the ramus and angle of the mandible | elevates and protracts the mandible | medial pterygoid branch of the mandibular division of the trigeminal nerve (V) | pterygoid branch of the maxillary a. | this muscle mirrors the masseter m. in position and action with the ramus of the mandible between the two mm. (Greek, pterygoid = wing-shaped) |
pupillae, dilator | outer margin of iris | inner margin of iris | dilates the pupil | sympathetic fibers via short ciliary nerves, synapsing in superior cervical sympathetic ganglion | ophthalmic a. | none |
pupillae, sphincter | encircles iris | encircles iris | constricts the pupil | parasympathetic fibers of oculomotor nerve (III), synapsing in ciliary ganglion | ophthalmic a. | none |
rectus capitis anterior | lateral mass of atlas | basilar portion of occipital bone | flexes the head | ventral primary ramus of spinal nerve C1 | deep cervical a. | none |
rectus capitis lateralis | transverse process of atlas | occipital bone anterolateral to foramen magnum | laterally bends the head | ventral primary ramus of spinal nerve C1 | deep cervical a. | none |
rectus, inferior | common tendinous ring at the apex of the orbit | sclera on the inferior surface of the eyeball | depresses and adducts the corneal part of the eyeball; rotates the superior pole of the iris laterally | oculomotor nerve (III), inferior division | ophthalmic a. | because this muscle approaches the eyeball from a medial direction, it has a rotational action on the iris |
rectus, lateral | common tendinous ring at the apex of the orbit | sclera on the lateral surface of the eyeball | abducts the corneal part of the eyeball | abducens nerve (VI) | ophthalmic a. | loss of function of the abducens nerve will cause the eye to be abducted |
rectus, medial | common tendinous ring at the apex of the orbit | sclera on the medial surface of the eyeball | adducts the corneal part of the eyeball | oculomotor nerve (III) (inferior division) | ophthalmic a. | this muscle directly opposes the action of the lateral rectus m. |
rectus, superior | common tendinous ring at the apex of the orbit | sclera on the superior surface of the eyeball | elevates and adducts the eyeball; rotates the superior pole of the iris medially | oculomotor nerve (III), superior division | ophthalmic a. | because this muscle approaches the eye from a medial position, it causes the iris to rotate medially |
risorius | fascia of the lateral cheek | skin of the angle (corner) of the mouth | draws the corner of the mouth laterally | buccal branches of the facial nerve (VII) | transverse facial a., facial a. | risorius is active in expressions of mirth (Latin, risorius = to laugh) |
salpingopharyngeus | inferior surface of the anteromedial end of the auditory tube cartilage | pharyngeal wall and superior border of the thyroid cartilage along with the palatopharyngeus m. | elevates the larynx | vagus nerve (X) via the pharyngeal plexus | ascending pharyngeal a. | like other muscles of the pharyngeal wall, salpingopharyngeus is derived from the fourth pharyngeal arch |
scalene, anterior | anterior tubercles of the transverse processes of vertebrae C3-C6 | scalene tubercle of the first rib | elevates the first rib; flexes and laterally bends the neck | brachial plexus, C5-C7 | ascending cervical a., a branch of the thyrocervical trunk | a muscle of inspiration; an important landmark of the neck; it is located between the subclavian vein and the subclavian artery; the roots of the brachial plexus pass posterior to it; the phrenic nerve crosses its anterior surface (Greek, scalene = uneven) |
scalene, middle | posterior tubercles of the transverse processes of vertebrae C2-C7 | upper surface of the first rib behind the subclavian artery | elevates the first rib; flexes and laterally bends the neck | brachial plexus, C3-C8 | ascending cervical a. | a muscle of respiration (inspiratory); also called scalenus medius; penetrated by the dorsal scapular n. and long thoracic n. (Greek, scalene = uneven) |
scalene, posterior | posterior tubercles of the transverse processes of vertebrae C5-C7 | lateral surface of the second rib | elevates the second rib; flexes and laterally bends the neck | brachial plexus, C7-C8 | ascending cervical a. | a muscle of respiration (inspiratory); it is the longest of the scalene muscles (Greek, scalene = uneven) |
sphenomeniscus | greater wing of the sphenoid | capsule and articular disk of the temporomandibular joint | pulls the articular disk forward in opening of the mouth | lateral pterygoid branch of mandibular division of trigeminal nerve (V) | pterygoid branch of the maxillary a. | sphenomeniscus is another name for the superior belly of the lateral pterygoid m. |
sphincter pupillae | encircles iris | encircles iris | constricts the pupil | parasympathetic fibers of oculomotor nerve (III), synapsing in ciliary ganglion | ophthalmic a. | none |
splenius | ligamentum nuchae and spines C7-T6 | capitis: mastoid process & superior nuchal line laterally; cervicis: posterior tubercles of C1-3 | extends and laterally bends neck and head; rotates head to same side | dorsal primary rami of spinal nerves C2-6 | supplied segmentally by: deep cervical a., posterior intercostal aa. | it gets its name from its broad, flat shape (Greek, splenius = a bandage) |
stapedius | walls of the pyramidal eminence | neck of the stapes | dampens vibration of the stapes | facial nerve (VII) | anterior tympanic a. | entirely enclosed in bone, except for its tendon; a derivative of the second pharyngeal arch |
sternocleidomastoid | sternal head: anterior surface of the manubrium; clavicular head: medial 1/3rd of the clavicle | mastoid process and lateral 1/2 of the superior nuchal line | draws the mastoid process down toward the same side which causes the chin to turn up toward the opposite side; acting together, the muscles of the two sides flex the neck | spinal accessory nerve (XI), with sensory supply from C2 & C3 (for proprioception) | sternocleidomastoid branch of the occipital a. | carotid sheath structures lie deep to it |
sternohyoid | posterior surfaces of both the manubrium and sternal end of the clavicle | lower border of the hyoid bone, medial to the omohyoid m. insertion | depresses/stabilizes the hyoid bone | ansa cervicalis | superior thyroid a. | sternohyoid overlies the sternothyroid and thyrohyoid mm. |
sternothyroid | posterior surface of the manubrium below the origin of the sternohyoid m. | oblique line of the thyroid cartilage | depresses/stabilizes the hyoid bone | ansa cervicalis | superior thyroid a. | sternothyroid lies deep to the sternohyoid m. |
styloglossus | anterior side of the styloid process | posterolateral side of the tongue | retracts and elevates the tongue | hypoglossal nerve (XII) | ascending pharyngeal a., ascending palatine branch of the facial a. | an extrinsic muscle of the tongue |
stylohyoid | posterior side of the styloid process | splits around the intermediate tendon of the digastric m. to insert on the body of the hyoid bone | elevates and retracts the hyoid bone | facial nerve (VII) | ascending pharyngeal a. | facial nerve innervates both the stylohyoid m. and the posterior belly of the digastric m. shortly after exiting from the stylomastoid foramen |
stylopharyngeus | medial side of the styloid process | superior border of the thyroid cartilage and also into the pharyngeal wall | elevates the larynx | glossopharyngeal nerve (IX) | ascending pharyngeal a. | stylopharyngeus, the only muscle innervated by IX, is the only muscle of the pharyngeal wall NOT innervated by the vagus (X) nerve; it is a derivative of the third pharyngeal arch |
superior oblique | apex of the orbit above the optic canal | sclera on the posterior superior surface of the eyeball | depresses and abducts the eyeball; rotates the superior pole of the iris medially | trochlear nerve (IV) | ophthalmic a. | passes through a fibrocartilagenous pulley known as the trochlea; when the eye is adducted, this muscle moves the cornea inferiorly |
superior pharyngeal constrictor | medial pterygoid plate, pterygoid hamulus, pterygomandibular raphe, mylohyoid line of mandible | pharyngeal tubercle and midline pharyngeal raphe | constricts the pharyngeal cavity | vagus (X), via the pharyngeal plexus | ascending pharyngeal a. | the most internal of the three pharyngeal constructor mm. |
superior rectus | common tendinous ring at the apex of the orbit | sclera on the superior surface of the eyeball | elevates and adducts the eyeball; rotates the superior pole of the iris medially | oculomotor nerve (III), superior division | ophthalmic a. | because this muscle approaches the eye from a medial position, it causes the iris to rotate medially |
temporalis | temporal fossa and the temporal fascia | coronoid process of the mandible and the anterior surface of the ramus of the mandible | elevates the mandible; retracts the mandible (posterior fibers) | anterior and posterior deep temporal nerves from the mandibular division of the trigeminal nerve (V) | anterior and posterior deep temporal aa. | a powerful chewing muscle; a derivative of the first pharyngeal arch |
tensor tympani | cartilagenous auditory tube and the greater wing of the sphenoid bone which lies adjacent to it | manubrium of the malleus | dampens vibrations of the tympanic membrane | medial pterygoid branch of the mandibular division of the trigeminal nerve (V) | superior tympanic branch of the middle meningeal a. | V3 innervates both tensor muscles of the head (tympani and veli palatini) which are derivatives of the first pharyngeal arch |