Sternocleidomastoid

Sternocleidomastoid is on both sides of the neck from the base of the skull to the clavicle and sternum. It is the only muscle that moves the head but is not attached to the vertebrae.

Below is the muscle study aid for massage therapy students.

If this muscle has spasms, the client can get vertigo.

Origins:

Manubrium of the sternum

Medial one third of the clavicle

Insertion:

Mastoid process

Actions:

Rotates head to opposite side

Flexes neck

Laterally flexes neck

Assists in forced inspiration

This muscle is the mirrored image of another muscle called splenius capitis, which you can read about under the neck muscles. It is important to note that that the carotid artery lies underneath this muscle and the external jugular vein is placed on top of it.

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