After fracture of the clavicle, the sternocleidomastoid muscle elevates the medial fragment of the bone.
Sometimes a mass, such as a sternocleidomastoid tumor, is noted in the affected muscle at the age of two to four weeks.
The lower sternocleidomastoid branch passes inferio-external to the hypoglossal nerve before descending into the substance of the muscle to which its name is derived.
Its top is also connected to the sternocleidomastoid muscle.
Usually the sternocleidomastoid muscle or the trapezius muscle is involved.
It is present on the face, over the upper portion of the sternocleidomastoid, at the nape of the neck, and overlying the sternum.
The superior surface is rough at its medial part and gives origin to the sternocleidomastoid muscle.
The sternocleidomastoid muscle is tested by asking the patient to turn their head to the left or right against resistance.
