Neck muscle and blood vessel anatomy, illustration. The major muscle labelled here, in this frontal view, is the paired muscle, the sternocleidomastoid (left). One of the largest neck muscles, it allows rotation of the head and flexion of the neck. It extends from the sternum in the chest, and the clavicle, to the mastoid process of the temporal bone of the skull. At centre is the larynx and the top of the trachea (windpipe, both grey). At right are two of the major paired blood vessels (with the other of the pair on the other side of the neck). The internal jugular vein (blue) is one of the major veins draining blood from the head and brain. The internal carotid artery (red) is one of the major arteries bringing blood to the brain.