Sternomastoid muscle

Sternocleidomastoid muscle

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Animation of the sternocleidomastoid muscle

The sternocleidomastoid muscle is a paired muscle in the human neck that runs obliquely across the side of the neck. It is one of the largest and most superficial cervical muscles. The primary actions of the muscle are rotation of the head to the opposite side and flexion of the neck. The sternocleidomastoid is innervated by the accessory nerve.

Structure

The sternocleidomastoid muscle originates from two locations: the manubrium of the sternum and the clavicle. It travels obliquely across the side of the neck and inserts at the mastoid process of the temporal bone of the skull.

The sternocleidomastoid muscle with nearby structures

Function

The sternocleidomastoid muscle has several actions: it rotates the head to the opposite side; it flexes the neck, and it aids in respiration.

Clinical significance

Dysfunction of the sternocleidomastoid muscle can result in a condition known as torticollis, or "wry neck".

See also

• List of muscles of the human body
• Neck muscle

External links

• AnatomyZone: Sternocleidomastoid Muscle