What Is Sternocleidomastoid?

Most people are unaware of the complex web of multiple muscles in the neck. There are many small muscles that assist in neck function, but one of the major movers is the sternocleidomastoid muscle.

Anatomy

• The sternocleidomastoid is the long band of muscle that extends from the collar bone (medial clavicle) and wraps around the side of the neck to attach at the base of the skull (mastoid process). (See Reference 1) The muscle exists on both sides of the neck.

Function

• The sternocleidomastoid works in conjunction with the smaller muscles of the neck to allow your head to rotate from side to side, tilt from right to left, and to nod forwards and backwards. The sternocleidomastoid also plays a roll in maintaining balance and equilibrium. (See Reference 2)

Assistors

• Other muscles that assist the sternocleidomastoid with head movement are the scalenes, which rest deep beneath the sternocleidomastoid, and the splenius which assists in counter-movement of the head from the back of the neck.

Injury

• Neck injuries most commonly occur from overuse, sudden movement, or direct impact to the head and shoulder region. According to The Cleveland Clinic symptoms most commonly include stiffness and aching, pain radiating in the head and shoulders, muscle spasms, headache, dizziness, or inability to move the extremities in severe cases. (See Reference 3)

Treatment

• Neck injuries are often treated with rest and immobilization, icing the area for 24-48 hours after injury, rehabilitation exercises, or x-rays, diagnostic imaging, and possibly surgery for more serious cases.