The nerves and vessels of the deeper layer of the left side of the neck. (Fourth layer of the neck.) The sternocleidomastoideus has been cut away, except at its origin and insertion, and the superficial veins have been removed. XX = Cross-section of external jugular vein near its termination. * = Cross-section of anterior jugular vein near its termination. X = Cross-section of common facial vein (near termination). * = Branch of cervical plexus to ansa hypoglossi. ** = Cross-section of superior thyroid vein (termination.) + = Sternocleidomastoid branch of superior thyroid artery (divided).