What does sternocleidomastoid muscle mean?
• STERNOCLEIDOMASTOID MUSCLE (noun) The noun STERNOCLEIDOMASTOID MUSCLE has 1 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 Familiarity information: STERNOCLEIDOMASTOID MUSCLE used as a noun is very rare.