sternocleidomastoid
/ˌstɜːr.noʊˌklaɪ.doʊˈmæs.tɔɪd/
noun
- A long muscle in the neck that helps turn and tilt the head.
- He strained his sternocleidomastoid from sleeping in an awkward position.
- The doctor palpated the sternocleidomastoid to check for swelling.
- The sternocleidomastoid is the muscle you can feel when you turn your head to the side.