Neck Muscles

Question 1

Platysma

Answer 1

O: upper part of thorax

I: mandible

A: draws corners of mouth and lower lip downward + laterally (expression of horror!)

In: facial nerve

Question 2

Sternocleidomastoid

Answer 2

O: sternum and medial third of clavicle

I: mastoid process of temporal bone

A: flexion of head and neck (bilaterally), lateral flexion and rotation of face to opposite side (unilaterally)

In: accessory nerve (motor), C2 and C3 (sensory)