ANATOMY

Detailed explanation-1: -The origin of the sternocleidomastoid is at the sternum and clavicle, and the insertion is at the mastoid process of the skull, which lies just behind the ear.

Detailed explanation-2: -The mastoid process is part of the temporal bone. It is the insertion for the sternocleidomastoid muscle.

Detailed explanation-3: -The sternocleidomastoids (SCMs) are superficially located neck muscles that play an important role in tilting your head and turning your neck, as well as other movements. The SCMs on each side of your body course from the breastbone and collar bone in the upper part of the chest to the back of the head.