Sternal Head of Sternocleidomastoid Muscle

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The sternal head of the sternocleidomastoid muscle (also known as the sternocleidomastoideus), along with the clavicular head, assist one another to stretch the cervical portion of the spinal column and the head at the atlanto-occipital joint. It's part of a long neck muscle called the sternocleidomastoid that goes from the mastoid process at the mastoid bone to the sternum and clavicle. This muscle rotates the head and neck.

The sternal head comes from the upper part of the anterior surface of the manubrium sterni, and is instructed to flow up, laterally, and back. It is a rounded fasiculus that is fleshy in back and tendinous in front. This and the other head, the clavicular head originate separately at a triangular interval. They eventually come together a little lower than the middle of the neck. This muscle gets worked into the lateral half of the superior nuchal line of the occipital bone. This occurs when the two heads merge into a thick muscle that gets tucked in to the lateral surface of the mastoid process, from its apex to its superior border, and by a thin aponeurosis by way of a strong tendon.