Neck Flashcards
What are the purposeful activities of the STERNOCLEIDOMASTOID (SCM)?
Watching an athletic event, socializing, driving
What are the unilateral muscle actions of the STERNOCLEIDOMASTOID (SCM)?
Neck ipsilateral lateral flexion
Neck contralateral rotation
(tilts head to same side and rotates it so face is turned superiorly toward opposite side)
What are bilateral muscle actions of the STERNOCLEIDOMASTOID (SCM)?
-Neck extension at OA (atlanto-occipital) joints
-Cervical vertebrae flexion (so that chin approaches manubrium)
-Superior cervical vertebrae extension with inferior vertebrae flexion (so chin is thrust forward with head kept level)
What are the muscle actions of the STERNOCLEIDOMASTOID (SCM) when the cervical vertebrae is fixed?
Manubrium and medial clavicle elevation (assisting pump handle action of deep respiration)
Where are the superior/medial attachments of the STERNOCLEIDOMASTOID (SCM)?
mastoid process (temporal bone)
superior nuchal line
Where are the inferior/lateral attachment of the STERNOCLEIDOMASTOID (SCM)?
Sternal head: Manubrium
Clavicular head: Medial 1/3 of clavicle
What nerves innervate the STERNOCLEIDOMASTOID (SCM)?
Spinal accessory nerve (CN XI)
Ventral Rami of C3, C4 (pain/proprioceptive fibers)
What is the purposeful activity of the PLATYSMA?
facial expression
What are the muscle actions of the PLATYSMA?
draws corners of mouth inferiorly and widens it (expressions of sadness/fright)
draws skin of neck superiorly when teeth are clenched
Where are the superior/medial attachments of the PLATYSMA?
inferior border of mandible, skin, and subcutaneous tissues of lower face
Where are the inferior/lateral attachments of the PLATYSMA?
pectoralis major and deltoid muscles
What nerve innervates the PLATYSMA?
cervical branch of facial nerve (CN VII)
