Unit 1 - Back: Superficial Neck Muscles (Ex. I)

Question 1

clavicular head of sternocleidomastoid

Answer 1

O: medial 1/3 of clavicle
I: mastoid process of T bone; S nuchal line of O bone
Inn: motor - accessory N (CN XI); pain and prioprioception - C plexus (C2, C3)
A: ipsilaterally flexes head and rotates contralaterally; together extends head and aids in respiration when head is fixed

Question 2

sternal head of sternocleidomastoid

Answer 2

O: manubrium of sternum
I: mastoid process of T bone; S nuchal line of O bone
Inn: motor - accessory N (CN XI); pain and prioprioception - cervical plexus (C2, C3)
A: ipsilaterally flexes head and rotates contralaterally; together extends head and aids in respiration when head is fixed