1. (noun) 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

• musculus sternocleidomastoideus
• sternocleido mastoideus
• sternocleidomastoid muscle

1. (noun) 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

• skeletal muscle
• striated muscle