Human Skeletal Muscles

Anatomical name of muscle

Main action of a muscle

Occipitofrontalis (frontal and Occipital bellies)

Forehead actions like raising eyebrows

Occipitofrontalis muscle is also called

Epicranius

Epicranial Aponeneurosis

Dense fibrous connective tissue; found in

Orbicularis Oculi

Closes eyes; ring shaped muscle located around the eyes

Procerus

flares nostrils; located over nasal bone

Nasalis

Compresses nasal cartilage, also causes a kind of “nostril flaring”

flexion

the angle between two bones is getting smaller;

extension

the angle between two bones gets bigger;

Buccinator

Horizontal span between jaws, compressing cheeks

Orbicularis Oris

Sphincter surround mouth, shaping the lips during speech/kissing

Mentalis

Pair on medial chin, elevates and protrudes lower lip

zygomatic major and zygomatic minor

Retract and elevate corners of mouth when smiling

Platysma

Depresses mandible and the soft structures of lower face

Extrinsic eye muscles

moves the eyeball

Intrinsic eye muscles

focus the eye for vision

six extrinsic eye muscles

• superior rectus

• inferior rectus

• lateral rectus

• medial rectus

• superior oblique

• inferior oblique

Superior rectus

move eyeball in respective directions

inferior rectus

move eyeball in respective directions

lateral rectus

move eyeball in respective directions

medial rectus

move eyeball in respective directions

superior oblique

attaches diagonally and rolls eyes downward

inferior oblique

attaches diagonally and rolls eye upward

temporalis

elevates mandible

masseter

elevates mandible and closes jaw grind teeth against food

Sternocleidomastoid (clavicular head and sternal head)

flexes neck and turns head

Trapezius

Large superficial muscle that moves scapula and supports arm

fasicle**

bundle of individual muscle**