Question

Unilateral contraction of the ____________ results in lateral flexion and rotation of the head to the opposite side; bilateral contraction flexes the head and neck.

Answer 1

The sternocleidomastoid muscle is responsible for lateral flexion and rotation of the head and neck.

Step-by-step explanation:

The subject of this question is Biology. The head, attached to the top of the vertebral column, is balanced, moved, and rotated by the neck muscles. The major muscle involved in this movement is the sternocleidomastoid. When this muscle contracts unilaterally, it results in lateral flexion and rotation of the head to the opposite side. When it contracts bilaterally, it flexes the head and neck.