Question

When both muscles of this pair are contracted simultaneously, they flex the neck forward. When both muscles of this pair are contracted simultaneously, they flex the neck forward. platysma semispinalis sternocleidomastoid trapezius

Answer 1

Sternocleidomastoid.

Step-by-step explanation:

Sternocleidomastoid muscles are located in the both side of neck and extend from the sternum. This muscle is originated from the clavicle and the manubrium of the sternum.

The main action of the sternocleidomastoid muscle is the lateral flexion of the head forward. This muscle also help in the unilateral contraction that helps in the chin elevation and rotate to the opposite side of the head. The levation of the head is also performed by sternocleidomastoid muscle.

Thus, the answer is sternocleidomastoid.