noun
sternocleidomastoid muscle; sternomastoid
Anatomical term for the large neck muscle that runs from behind the ear to the collarbone and sternum.
胸鎖乳突筋は首を回すときに使われる筋肉です。
The sternocleidomastoid muscle is used when turning the neck.
Compound of 胸 (kyō, 'chest'), 鎖 (sa, 'chain' or 'collarbone'), 乳突 (nyūtotsu, 'mastoid process'), and 筋 (kin, 'muscle'), reflecting the muscle's attachment points.