The sternocleidomastoid muscle is a prominent muscle in the neck that plays a key role in head movement and rotation. It originates from two points: the sternum (manubrium) and the clavicle (collarbone), hence the name "sternocleidomastoid." The muscle inserts at the mastoid process of the temporal bone of the skull.
Here are some important points regarding the sternocleidomastoid muscle:
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Function:
- Head Movement: It assists in turning the head to the opposite side and tilting the head to the same side.
- Flexion: When both sides contract together, they help to flex the neck forward.
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Innervation: The sternocleidomastoid is primarily innervated by the spinal accessory nerve (cranial nerve XI) and has contributions from the cervical plexus.
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Clinical Relevance:
- Tension in the sternocleidomastoid can lead to neck pain and headaches.
- Abnormalities in its function can be associated with conditions like torticollis (wry neck).
- It can also be affected in certain syndromes and conditions affecting posture and musculoskeletal health.
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Anatomical Landmarks: It serves as a landmark in clinical practice for the location of other structures in the neck, such as major arteries and veins.
Overall, the sternocleidomastoid muscle is significant for its role in movement and its clinical implications in various neck-related conditions.