PEDS100 Chapter Notes -Masseter Muscle, Mastoid Part Of The Temporal Bone, Occipital Bone
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25 Nov 2011
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Muscles of the Axial Skeleton
-position head and vertebral column
-move rib cage
~ 60% of skeletal muscles are axial muscles
1. Muscles of head and neck
2. Muscles of vertebral column
3. Muscles of abdomen
4. Muscles of pelvic floor
Muscles of Facial Expression: don’t need to know origins/insertion.
-Masseter muscle helps close mouth
-Buccinator helps with chewing
-Risorius helps with smiling
Zygomaticus major/minor help with smiling
Occipitofrontalis: muscles on front and back of skull that can pull skin on top of head
back and forth, raise/lower eyebrows
Muscles of the Neck:
Platysma: muscle that flares out, attaches to skin, flares out in neck
Sternocleidomastoid: palpable
O:Clavicle, manubrium
I: Mastoid process (“ball” just behind ear)
A: Bilaterally flexes vertebral column in neck region, extends head, elevates sternum
on forced inspiration. Unilaterally laterally flexes & rotation of head towards side
opposite contracting muscles
Scalenes(3): Deep, not palpable. Anterior (C3-C6) to first rib, Middle(C2-C7) to first
rib, Posterior (C4-C6) to 2nd rib. All attach separately. Space between muscles is
where brachial plexus comes out. If muscles are stretched they can damage brachial
plexus.
O: C2-C7 (transverse processes)
I: Ribs 1 & 2
A: Flexes laterally, elevates ribs
-The intrinsic muscles of the back form 3 distinct layers:
•Superficial: move the neck
•Intermediate: extend the vertebral column
•Deep: interconnect vertebrae