Muscles Anatomy Exam 1

occipitofrontalis

occipitofrontalis

origin: 4 bellies (2 frontal, 2 occipital)

insertion: epicranial aponeurosis (galea aponeuratica)

innervation: CN VII

action:move scalp forward/backward, raise eyebrows in expression

orbicularis oculi

origin: medial palpebral ligament

insertion: lateral palpebral raphe

innervation: CN VII

action: close eyelids, assist lacrimal flow

currugator supercili

innervation: CN VII

action: draws eyebrows medially and inferior

compressor naci

innervation: CN VII

action: elevate corner of nostrils

dilator nasi

innervation: CN VII

action: dilate nares

procerus

innervation: CN VII

acton: wrinkle nose

orbicularis oris

innervation: CN VII

action: compress lips together, keep food between teeth during mastication

buccinator

origin: maxilla and mandible

insertion: orbicularis oris

innervation: CN VII

action: resist dissension when blowing/whistling, active in smiling, keep food between teeth, active during sucking, blowing, whistling, press cheek against molar teeth

masseter

origin: zygomatic arch

insertion: lateral mandible

innervation: CN V (trigeminal mandibular division)

action: elevate mandible to occlude teeth

temporalis

origin: floor of temporal fossa

insertion: coronoid process of mandible

innervation: CN V (trigeminal mandibular division)

action: elevate and retract mandible

lateral pterygoid

innervation: CN V (trigeminal mandibular division)

action: depress, protrude, and side to side movement of mandible

medial pterygoid

innervation: CN V (trigeminal mandibular division)

action: elevates mandible

levator anguli oris

action: aids in grinning

mentalis

action: elevates and protrudes lower lip

platysma

origin: pectorals major, deltoid

insertion: mandible

innervation: cervical branch of CN VII

action: depresses mandible, draws outer part of lower lip down and back (pouting)

levator palpebrae superioris

innervation: CN III

action: elevate superior eyelid

superior rectus

innervation: CN III

inferior rectus

innervation: CN III

medial rectus

innervation: CN III

lateral rectus

innervation: CN VI

superior oblique

innervation: CN IV

inferior oblique

innervation: CN III

sphincter pupillae (circular, pupillary sphincter)

innervation: CN III

action: contraction causes constriction (mitosis or myosis) of pupil; parasympathetic

dilator pupillae (radial, pupil dilator)

innervation: CN III

action: contraction causes puil dilation (mydriasis); sympathetic

tensor tympani

innervation: CN V (trigeminal mandibular division)

stapedius

innervation: CN VII

frontal sinus

innervation: supraorbital nerves of CN V1 (trigeminal opthalmic division)

genioglossus

innervation: CN XII

action: depresses tongue (mainly center); protrudes tongue

hypoglossus

innervation: CN XII

action: depresses and retracts tongue

styloglossus

innervation: CN XII

action: retracts and elevates tongue

palatoglossus

innervation: CN X (pharyngeal branch)

action: elevates posterior part of tongue, depresses soft palate

digastric

origin: anterior belly- mandible; posterior belly- mastoid process (temporal bone)

insertion: hyoid bone

innervation: anterior- mylohyoid; posterior- CN VII

action: elevates hyoid bone and depresses mandible, as in opening mouth

stylohyoid

origin: styloid process of temporal bone

insertion: hyoid bone

innervation: CN VII

action: elevates hyoid bone and draws it posteriorly (elongating floor of mouth during swallowing)

mylohyoid

origin: mandible

insertion: hyoid bone

innervation: mylohoid nerve

action: elevates hyoid bone, raises floor of mouth, elevates tongue

geniohyoid

origin: mandible

insertion: hyoid bone

innervation: C1

action: pulls hyoid bone anterosuperiorly, shortens floor of mouth, widens pharynx

omohyoid

origin: scapula

insertion: hyoid bone

innervation: C1-C3

action: depresses, retracts, and steadies hyoid bone

sternohyoid

origin: manubrium of sternum and medial clavicle

insertion: hyoid bone

innervation: C1-C3

action: depresses hyoid bone

sternothyroid

origin: manubrium of sternum

insertion: thyroid cartilage of larynx

innervation: C2, C3

action: depresses thyroid and thyroid cartilage (Adam’s apple) of larynx

thyrohyoid

origin: thyroid cartilage of larynx

insertion: hyoid bone

innervation: C1

action: elevates thyroid cartilage, depresses hyoid bone

levator scapulae

origin: C1-C4

insertion: scapula

innervation: C3-C5

action: elevates scapula

semispinalis

innervation: occipital nerve

action: extend the head

longissimus capitis

origin: C3-T-5

insertion: mastoid process (posteriorly)

action: extend the head

anterior/middle/posterior scalene

origin: C2-C7

insertion: 1st and 2nd ribs

innervation: C4-C8

action: elevate ribs and rotate neck

sternocleidomastoid (SCM)

origin: two heads: sternal head (manubrium of sternum) and clavicular head (medial 1/3 of clavicle)

insertion: mastoid process of temporal bones

innervation: CN XI

action: bilaterally- flexion of head (chin towards sternum), elevate sternum during forceful inhalation; unilaterally- rotate head

trapezius

origin: occipital protuberance and vertebrae spinous processes

insertion: clavicle and accordion process and spine of scapula

innervation: CN XI

action: elevate, retract, and rotate scapula; elevate pectoral girdle; depress shoulders; rotate scapula upward; bilateral contraction extends neck, unilateral contraction produces lateral flexion to the same side