Axial Muscles OAI

occipitofrontalis frontal belly action

raises eyebrows, wrinkles forehead

occipitofrontalis frontal belly origin

epicranial aponeurosis

occipitofrontalis frontal belly insertion

skin of eyebrow and bridge of nose

orbicularis oculi action

closes eye

orbicularis oculi origin

medial margin of orbit

orbicularis oculi insertion

skin around eyelids

levator labii superioris action

elevates upper lip

levator labii superioris origin

inferior margin of orbit

levator labii superioris insertion

orbicularis oris

depressor labii inferioris action

depresses lower lip

depressor labii inferioris and mentalis origin

mandible (O)

depressor labii inferioris insertion

skin of lower lip

orbicularis oris action

compresses, purses lips

orbicularis oris origin

maxilla and mandible

orbicularis oris insertion

lips

mentalis action

protrudes lower lip (pouting)

mentalis insertion

skin of chin

sternocleidomastoid action

bilaterally, flex neck

unilaterally, laterally flex neck and turns face to opposite side

sternocleidomastoid origin

clavicle and sternum

sternocleidomastoid insertion

mastoid process of temporal bone

inferior rectus action

eyes look down

inferior rectus, medial rectus, superior rectus, lateral rectus, superior oblique origin

sphenoid

inferior rectus insertion

inferior orbital surface

medial rectus action

eyes look medially

medial rectus insertion

medial surface of orbit

superior rectus action

eyes look up

superior rectus insertion

superior surface of orbit

lateral rectus action

eyes look laterally

lateral rectus insertion

lateral surface of orbit

inferior oblique action

eye rolls, looks up

inferior oblique origin

maxilla

inferior oblique insertion

inferior/lateral surface of orbit

superior oblique action

eye rolls, looks down

superior oblique insertion

superior/lateral surface of orbit

zygomaticus major action

elevates corner of mouth and draws it laterally

zygomaticus major and minor origin

zygomatic bone

zygomaticus major insertion

muscles at angle of mouth

zygomaticus minor action

elevates upper lip

zygomaticus minor insertion

upper lip

temporalis action

elevates/closes jaw

temporalis origin

temporal bone

temporalis insertion

coronoid process of mandible

masseter action

elevates mandible

masseter origin

zygomatic arch

masseter insertion

mandible (I)

diaphragm action

when contracted, flattens and increases vertical dimension of thoracic cavity for inhalation

when relaxed, moves superiorly and decreases vertical dimension of cavity for exhalation

diaphragm origin

xiphoid process of sternum/costal cartilage of ribs/lumbar vertebrae and discs

diaphragm insertion

central tendon (towards center of diaphragm)

external intercostals action

when contracted, elevate ribs and increase anteroposterior dimension of thoracic cavity for inhalation

when relaxed, depress ribs and decrease dimension of cavity for exhalation

external intercostals origin

inferior border of rib above (O)

external intercostals insertion

superior border of rib below (I)

internal intercostals action

when contracted, depresses ribs during forced exhalation

internal intercostals origin

superior border of rib below (o)

internal intercostals insertion

inferior border of rib above (I)

rectus abdominis action

flexes vertebral column and compresses abdomen

rectus abdominis origin

pubic crest/pubic symphysis

rectus abdominis insertion

ribs 5-7/xiphoid process of sternum

external oblique action

acting together (bilaterally)- compress abdomen/flex vertebral column

acting separately (unilaterally)- lateral flexion of vertebral column

external oblique origin

lower ribs

external oblique insertion

iliac crest of ilium/linea alba

internal oblique action

bilaterally- compress abdomen/flex vertebral column

unilaterally- lateral flexion of vertebral column and rotates column to same side

internal oblique origin

iliac crest of ilium

internal oblique insertion

lower three ribs/linea alba

transverse abdominis action

compresses abdomen

transverse abdominis origin

ilia crest of ilium/ribs

transverse abdominis insertion

xiphoid process of sternum, linea alba (midline) and pubic bone

erector spinae action

bilaterally- extend vertebral column and maintain posture

unilaterally- rotate and laterally flex vertebral column

erector spinae origin/insertion

large muscle group extending from sacrum to the base of the skill

attach to vertebrae and ribs along the way