The deep veins and arteries of the neck and the great venous and arterial trunks of the thorax. Upon both sides the sternocleidomastoidei and the infra-hyoid muscles have been partly cut away, the mylohyoid and digastric divided, and the sternum, together with the portions of the ribs and clavicle, removed. * = Commencement of right innominate vein. ** = Posterior root of external jugular vein. + = Oral mucous membrane. +* = Anastomosis between hypoglossal and lingual nerves.