Sternocleidomastoid is a prominent neck muscle that plays a key role in head movement, allowing rotation and flexion. It also assists in breathing by elevating the sternum during inspiration. Its position and strength contribute significantly to the stability and mobility of the neck.
The name "Sternocleidomastoid" comes from its three points of attachment: the sternum (sterno-), the clavicle (-cleido-), and the mastoid process (-mastoideus) of the skull.
Without the Sternocleidomastoid, the head would lack efficient rotational and flexion capability, severely impacting actions like nodding or turning the head. Breathing could also become less effective due to reduced assistance with expanding the rib cage.
Image
