Muscles Of Head And Neck

Front 1

Frontalis:

Back 1

Elevates eyebrows in glancing upward and expressions of surprise or fright; draws scalp forward and wrinkles skin of forehead

Front 2

Occipitalis:

Back 2

Retracts scalp; fixes galea aponeurotica so frontalis can act on eyebrows

Front 3

Oribiculus oculi:

Back 3

sphuncter of the eyelids; closes eye in blinking squinting, and sleep; aids in flow of tears across eye

Front 4

Orbicularis Oris:

Back 4

Encircles mouth closes lips, protrudes lops as in kissing; uniquely developed in humans for speech

Front 5

Levator Labii Superioris:

Back 5

Elevates and everts upper lip in sad, sneering, or serious expressions

Front 6

Zygomaticus Major:

Back 6

Draws angle of mouth upward and laterally in laughing

Front 7

Zygomaticus minor:

Back 7

Elevates upper lip, exposes upper teeth in smiling or sneering

Front 8

Risorius:

Back 8

Draws angle of mouth laterally in expressions of laughing, horror, or disdain

Front 9

Depressor Anguli Oris:

Back 9

Draws angle of mouth laterally and downward in opening mouth or sad expressions

Front 10

Depressor Labii Inferioris:

Back 10

Draws lower lip downward and laterally in chewing and expressions of melancholy or doubt

Front 11

Mentalis:

Back 11

Elevates and protrudes lower lip in drinking, pouting and expressions of doubt or disdain; elevates and wrinkles skin of chin

Front 12

Buccinator:

Back 12

Compresses cheek against teeth and gums; directs food between molars; retracts cheek from teeth when mouth is closing to prevent biting the cheek; expels air and liquid

Front 13

Temporalis:

Back 13

elevation, retraction, and lateral and medial excursion of the mandible

Front 14

Masseter:

Back 14

elevation of the mandible, with smaller roles in protraction, retraction, and lateral and medial excursion

Front 15

Medial pterygoid:

Back 15

elevation, protraction, and lateral and medial excursion of the mandible

Front 16

Lateral pterygoid:

Back 16

depression(in wide opening of the mouth), protraction, and lateral and medial excursion of the mandible

Front 17

Digrastic:

Back 17

depresses mandible when hyoid is fixed; opens mouth widely; as when ingesting food or yawning; elevates hyoid when mandible is fixed

Front 18

Geniohyoid:

Back 18

depresses mandible when hyoid is fixed; elevates and protracts hyoid when mandible is fixed

Front 19

Mylohyoid:

Back 19

spans mandible from side to side and forms floor of mouth; elevates floor of mouth in initial stage of swallowing

Front 20

Sylohoid:

Back 20

elevates and retracts hyoid, elongating floor of mouth; roles in speech, chewing, and swallowing are not yet clearly understood

Front 21

Omohyoid:

Back 21

depresses hyoid after it has been elevated

Front 22

Sternohyoid:

Back 22

depresses larynx after it has been elevated in swallowing and vocalization; aids in singing low notes

Front 23

Sternocleidomastoid:

Back 23

unilateral action tilts head slightly upward and toward the opposite side, as in looking over one's contralateral shoulder. The most common action is probably rotating the head to the left or right. Bilateral action draws the head straight forward and down, as when eating or reading. aids in deep breathing when head is fixed

Front 24

Anterior, middle, and posterior scalenes:

Back 24

unilateral contraction causes ipsilateral flexion or contralateral rotation, depending on action of other muscles. Bilateral contraction flexes neck. ifspine is fixed, scalenes elevate ribs 1--2 and aid in breathing

Front 25

Trapezius:

Back 25

extends and laterally flexes neck.

Front 26

Spenius capitis and splenius cervicis:

Back 26

acting unilaterally, produce ipsilateral flexion and slight rotation of the head; extend head when acting bilaterally

Front 27

Semispinalis Capitis and semispinalis cervicis:

Back 27

extend and contralaterally rotate the head

Front 28

Levator Scapulae:

Back 28

elevates scapula if cervical vertebrae are fixed; flexes neck laterally if scapula is fixed; retracts scapula and braces shoulder; rotates scapula and depresses apex of shoulder

Front 29

Levator Scapulae (O & I) :

Back 29

O: transverse processes of vertebrae c1-c4

I: Superior angle to medial border of scapula

Front 30

Sternocleidomastoid (O & I) :

Back 30

O: manubrium of sternum; medial one third of clavicle

I: mastoid process; lateral half of superior nuchal line

Front 31

Anterior, middle, and posterior scalenes (O & I) :

Back 31

O: transverse processes of all cervical vertebrae (C1-C7)

I: ribs 1-2

Front 32

Trapezius (O & I) :

Back 32

O: external occipital protuberance; medial one-third of superior nuchal line; nuchal ligament; spinous processes of vertebrae C7-T3 or T4

I: acromion and spine of scapula; lateral one-third of clavicle

Front 33

Splenius capitis and splenius cervicis (O & I ):

Back 33

O: inferior half of nuchal ligament; spinous processes of vertebrae c7-t6

I: mastoid process and occipital bone just inferior to superior nuchal line; cervical vertebrae C1-C2 or C3