Axial Muscles

Buccinator

1. action - origin maxilla & mandible, insertion orbicularis oris, action = retracts angle of mouth, chewing
   

Orbicularis oris

origin maxilla & mandible, insertion skin around mouth, action protrudes (purses) lips

Zygomaticus minor

origin zygomatic bone, insertion skin of superior lip, action elevates corner of mouth (smile)

Zygomaticus major

origin zygomatic bone, insertion corner of mouth, action draws angle of mouth upwards (smile)

Frontal belly of epicranius
("frontalis")

origin frontal bone, insertion epicranial aponeurosis, action wrinkles forehead & raises eyebrows

Occipital belly of epicranius
("occipitalis")

origin occipital bone, insertion epicranial aponeurosis, action retracts scalp

Orbicularis oculi

origin frontal & maxillary bones, insertion, eyelids, action closes eye (blink)

temporalis

origin temporal fossa, insertion coronoid process of mandible, action elevates mandible

Masseter

origin zygomatic arch, insertion mandible, action elevates mandible

Mylohyoid

origin mandible, insertion hyoid bone, action elevates hyoid & floor of mou

Thyrohyoid

origin (thyroid?) cartilage, insertion hyoid bone, action depresses hyoid bone & elevates larynx

Sternothyroid

origin manubrium, insertion thyroid cartilage, action depresses larynx

Omohyoid

origin scapula, insertion hyoid bone, action depresses hyoid

Sternocleidomastoid

origin manubrium & clavicle, insertion mastoid action process rotates & flexes head

Erector spinae group

origin iliac crest, sacrum & vertebrae ribs, insertion vertebrae & mastoid process of temporal bone, action extends head, neck & vertebral column

internal intercostal

origin rib below, insertion rib above, action depresses ribs during exhalation "Intercostales interni"

External intercostal

origin rib above, insertion rib below, action elevates ribs during inhalation

Diaphragm inferior

origin internal ribs 7-12, insertion central tendon, action expands thoracic cavity

Internal abdominal oblique

origin oblique iliac crest & thoracolumbar fascia, insertion linea alba & lower 4 ribs compresses abdomen; action flexes & rotates vertebral column

transversus abdominis

origin iliac crest & cartilage of lower 6 ribs, insertion linea alba, action compresses abdomen

External abdominal oblique

origin lower eight ribs, insertion linea alba & iliac crest, action compresses abdomen; flexes & rotates vertebral column

Rectus abdominis pubis
*

origin pubis, insertion cartilage of ribs 5-7 & xiphoid process, action flexes vertebral column & compresses abdomen

Muscle fibers of internal intercostal

Muscle fibers run away from sternum and towards head, facilitating the depression of the ribs during exhalation.

Muscle fibers of external intercostal

oriented diagonally downward from one rib to the rib below, toward sternum facilitating the elevation of the ribs during inhalation, air intake.