Learn That Word

Synonyms for Sternocleido Mastoideus (same or very similar meaning)

WordNet sense 1 (one of two thick muscles running from the sternum and clavicle to the mastoid and occipital bone; turns head obliquely to the opposite side; when acting together they flex the neck and extend the head):
sternocleidomastoid, musculus sternocleidomastoideus, sternocleidomastoid muscle

From the ODE community, based on WordNetadd/edit