Sternocleidomastoid
Flexes and laterally rotates the head
The sternocleidomastoid (SCM) is a large muscle that is found in the neck. It is named for its points of origin: the sternum (sterno-), clavicle (cleido-), and mastoid process of the temporal bone (-mastoid).
The SCM is responsible for several movements of the head and neck. If one side of the muscle contracts, the head is rotated towards the opposite side, while if both muscles contract, the head is flexed forward towards the chest.
The SCM can become tight or sore from poor posture, stress, or injury. This can result in stiffness, headaches, or pain in the neck or upper back. Stretching and massage can help to relieve tension in the muscle, while strengthening exercises can improve its function. Treatment of stiff or tight SCM may depend on the underlying cause, and may require medical intervention in some cases.
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