Human Anatomy Head, Neck, Thorax Muscles

Occipitofrontalis Action

occipital belly: retracts scalp, frontal belly: elevates eyebrows & wrinkles skin of forehead, protracts scalp

Occipitofrontalis Innervation

facial nerve CN VII

Orbicularis Oculi Action

closes eyelid gently & tightly

Orbicularis Oculi Innervation

facial nerve CN VII

Corrugator Supercilii Action

draws eyebrows medially and inferiorly

Corrugator Supercilii Innervation

facial nerve CN VII

Orbicularis Oris Action

tonus closes oral fissure, phasic contraction compresses & protrudes lips or resists distension

Orbicularis Oris Innervation

facial nerve CN VII

Levator Labii Superioris Action

part of dilators of mouth, retract and/or evert upper lip, deepen nasolabial sulcus

Levator Labii Superioris Innervation

facial nerve CN VII

Buccinator Action

presses cheek against molar teeth, works w/ tongue to keep food b/w occlusal surfaces & out of oral vestibule, resists distension when blowing

Buccinator Innervation

facial nerve CN VII

Zygomaticus Major Action

part of dilators of mouth, elevate corner of mouth

Zygomaticus Major Innervation

facial nerve CN VII

Zygomaticus Minor Action

part of dilators of mouth, retract and/or evert upper lip, deepen nasolabial sulcus

Zygomaticus Minor Innervation

facial nerve CN VII

Levator Anguli Oris Action

part of dilators of mouth, widens oral fissure when grinning or grimacing

Levator Anguli Oris Innervation

facial nerve CN VII

Risorius Action

part of dilators of mouth, bilaterally depresses corner of mouth

Risorius Innervation

facial nerve CN VII

Depressor Anguli Oris Action

part of dilators of mouth, bilaterally depresses corner of mouth

Depressor Anguli Oris Innervation

facial nerve CN VII

Depressor Labii Inferioris Action

part of dilators of mouth, retracts and/or everts lower lip

Depressor Labii Inferioris Innervation

facial nerve CN VII

Mentalis Action

elevates & protrudes lower lip, elevates skin of chin

Mentalis Innervation

facial nerve CN VII

Platysma Action

depresses mandible, tenses skin of inferior face & neck, draws corners of mouth inferiorly & widens it, draws skin of neck superiorly when teeth are clenched

Platysma Innervation

cervical branch of facial nerve CN VII

Nasalis Action

transverse part: depresses medial end of eyebrow, wrinkles nose. alar part: depresses ala laterally, flaring nostrils, helps elevate upper lip

Nasalis Innervation

facial nerve CN VII

Levator Labii Superioris Alaeque Nasi Action

depresses ala laterally, flaring nostrils, helps elevate upper lip

Levator Labii Superioris Alaeque Nasi Innervation

facial nerve CN VII

Procerus Action

depresses medial end of eyebrow, wrinkles nose

Procerus Innervation

facial nerve CN VII

Levator Palpebrae Superioris Action

elevates superior eyelid

Levator Palpebrae Superioris Innervation

oculomotor nerve CN III, deep layer (superior tarsal muscle): sympathetic fibers

Superior Oblique Action

abduct, depress, medially rotate eyeball

Superior Oblique Innervation

trochlear nerve CN IV

Inferior Oblique Action

abduct, elevate, laterally rotate eyeball

Inferior Oblique Innervation

oculomotor nerve CN III

Superior Rectus Action

elevate, adduct, medially rotate eyeball

Superior Rectus Innervation

oculomotor nerve CN III

Inferior Rectus Action

depress, adduct, laterally rotate eyeball

Inferior Rectus Innervation

oculomotor nerve CN III

Medial Rectus Action

adduct eyeball

Medial Rectus Innervation

oculomotor nerve CN III

Lateral Rectus Action

abduct eyeball

Lateral Rectus Innervation

abducens nerve CN VI

Temporalis Action

elevates & retracts mandible

Temporalis Innervation

anterior trunk of mandibular nerve CN V3 via deep temporal branches

Masseter Action

elevates and slightly protrudes mandible

Masseter Innervation

anterior trunk of mandibular nerve CN V3 via masseteric nerve

Lateral Pterygoid Action

bilaterally protracts mandible & depresses chin, unilaterally swings jaw toward contralateral side, alternate unilateral contraction produces larger lateral chewing movements

Lateral Pterygoid Innervation

anterior trunk of mandibular nerve CN V3 via lateral pterygoid nerve

Medial Pterygoid Action

acts w/ masseter to elevate mandible, contributes to protrusion, alternate unilateral activity produces smaller grinding movements

Medial Pterygoid Innervation

main trunk of mandibular nerve CN V3 via medial pterygoid nerve

Palatoglossus Action

elevates posterior part of tongue, depresses soft palate

Palatoglossus Innervation

pharyngeal branch of vagus nerve CN X via pharyngeal plexus

Hyoglossus Action

depresses and shortens tongue, pulls sides of tongue inferiorly

Hyoglossus Innervation

hypoglossal nerve CN XII

Styloglossus Action

retrudes tongue & curls its sides, working with genioglossus to form a central trough during swallowing

Styloglossus Innervation

hypoglossal nerve CN XII

Genioglossus Action

bilaterally protrudes and depresses tongue, unilaterally deviates to opposite side

Genioglossus Innervation

hypoglossal nerve CN XII

Sternocleidomastoid Action

unilaterally tilts head to same side, rotates head so face is turned superiorly toward opposite side. bilaterally extends neck at atlanto-occipital joints, flexes cervical vertebrae, extends superior cervical vertebrae while flexing inferior vertebrae so chin is thrust forward w/ head kept level. w/ cervical vertebrae fixed, may elevate manubrium & medial ends of clavicles, assisting pump-handle action of deep respiration

Sternocleidomastoid SA

lateral surface of mastoid process of temporal bone, lateral 1/2 of superior nuchal line

Sternocleidomastoid IA

sternal head: anterior surface of manubrium of sternum, clavicular head: superior surface of medial 1/3 of clavicle

Sternocleidomastoid Innervation

spinal accessory nerve CN XI (motor) & C3, C4 nerves (pain & proprioception)

Longus Colli Action

unilaterally flexes neck w/ rotation to opposite side

Longus Colli Innervation

anterior rami C2-C6

Longus Capitis Action

flexes head

Longus Capitis Innervation

anterior rami C1-C3

Rectus Capitis Lateralis Action

flexes head & helps stabilize it

Rectus Capitis Lateralis Innervation

branches from loop b/w C1 & C2 spinal nerves

Splenius Capitis Action

laterally flexes & rotates head & neck to same side, bilaterally extends head & neck

Splenius Capitis Innervation

posterior rami of middle cervical spinal nerves

Levator Scapulae Action

elevates scapula, rotates glenoid cavity inferiorly by rotating scapula

Levator Scapulae Innervation

dorsal scapular nerve C4, C5 & cervical nerves C3, C4

Anterior Scalene Action

lateral flexion of neck, elevates 1st rib during forced inspiration

Anterior Scalene SA

transverse processes of C3-C6

Anterior Scalene IA

1st rib

Anterior Scalene Innervation

cervical spinal nerves C4-C6

Middle Scalene Action

lateral flexion of neck, elevates 1st rib during forced inspiration

Middle Scalene SA

posterior tubercles of transverse processes of C5-C7

Middle Scalene IA

superior surface of 1st rib, posterior to groove for subclavian artery

Middle Scalene Innervation

anterior rami of cervical spinal nerves

Posterior Scalene Action

lateral flexion of neck, elevates 2nd rib during forced inspiration

Posterior Scalene SA

posterior tubercles of transverse processes of C5-C7

Posterior Scalene IA

external border of 2nd rib

Posterior Scalene Innervation

anterior rami of cervical spinal nerves C7 & C8

Mylohyoid Action

elevates hyoid, floor of mouth, & tongue during swallowing & speaking

Mylohyoid Innervation

mandibular nerve CN V3

Geniohyoid Action

pulls hyoid anterosuperiorly, shortens floor of mouth, widens pharynx

Geniohyoid Innervation

hypoglossal nerve CN XII

Stylohyoid Action

elevates & retracts hyoid

Stylohyoid Innervation

facial nerve CN VII

Digastric Action

working w/ infrahyoid muscles, depresses mandible against resistance. elevates & steadies hyoid during swallowing & speaking

Digastric Innervation

anterior belly: mandibular nerve CN V3. posterior belly: facial nerve CN VII

Sternohyoid Action

depresses hyoid after elevation during swallowing

Sternohyoid Innervation

ansa cervicalis