Question

multiple choice question
bilateral contraction of the sternocleidomastoid muscles functions to
rotate the head
laterally flex the neck
extend the neck
flex the neck

Explanation:

The sternocleidomastoid muscles, when bilaterally contracted, flex the neck. Unilateral contraction rotates the head and laterally flexes the neck. Neck - extension is not a function of the bilateral contraction of these muscles.

Answer:

flex the neck