Sternocleidomastoid Muscle: The Primary Head Flexor

Yes, the prime mover of head flexion is a two-headed muscle called the sternocleidomastoid muscle (SCM). The SCM originates from the sternum and clavicle and inserts into the mastoid process of the temporal bone behind the ear. It works together with other neck flexor muscles to flex the head forward and tilt it to one side.