The |sternocleidomastoid| muscle is located in the neck. It is a thin, broad muscle that narrows at the center. It originates from two heads, one from the |sternum| (breastbone) and one from the clavical (collar bone), and runs upward, inserting into the mastoid (the |temporal bone| behind the |ear|). This muscle is used to tilt the head from side to side.
