sternocleidomastoid muscle function

What is Sternocleidomastoid Muscle? The sternocleidomastoid muscle is a 2-headed neck muscle, true to its name bears joining to the manubrium of the sternum (Sterno), the clavicle (cleido), & the mastoid process of the temporal bone (mastoid).  It is a lengthened, bilateral muscle of the neck, which functions to flex the neck both laterally & anteriorly, as well as rotate the head opposite…