Chapter 11: Axial Skeletal Muscles Flashcards
less movable (more stable) attachment point
origin
more movable (less stable) attachment point
insertion
muscle that contracts during movement
agonist
assists agonist in generating movement
synergist
relaxes during joint movement
antagonist
frontal belly of occipitofrontalis function
moves scalp, eyebrows; wrinkles skin of forehead
frontal belly of occipitofrontalis origin & insertion
origin- epicranial aponeurosis
insertion- eyebrow skin
depressor anguli oris function
“frown” muscle
depressor anguli oris origin & insertion
origin- body of mandible
insertion- skin at inferior corner (angle) of mouth
zygomaticus major function
“smile” muscle
zygomaticus major origin & insertion
origin- zygomatic bone
insertion- skin at superolateral edge of mouth
masseter function
prime mover of jaw closure
masseter origin & insertion
origin- zygomatic arch
insertion- ramus (lateral surface) & angle of mandible
sternocleidomastoid function
unilateral action: lateral flexion
bilateral action: flexes neck
splenius capitis function
unilateral action: turns head to same side
bilateral action: extends head/neck
splenius capitis origin & insertion
origin- ligamentum nuchae & spinous processes of c7-t3
insertion- occipital bone and mastoid process of temporal bone
external oblique function
unilateral action: lateral flexion of vertebral column
bilateral action: forced exhalation
external oblique origin & insertion
origin- external & inferior borders of the inferior 8 ribs
insertion- linea alba, some to iliac crest
rectus abdominis function
forced exhalation
rectus abdominis origin & insertion
origin- superior surface of pubis near symphysis
insertion- xiphoid process of sternum
