The purpose of this paper is to present four cases in which head and neck trauma of various types produced changes in the internal carotid artery and its branches, demonstrated by arteriography. The entity of thrombosis and sometimes cerebral embolism following trauma has been described frequently from the clinical aspect, recent reviews being those of Pitner (7), Shillito (10), and Murray (6). Wolpert and Schechter (12) described post-traumatic occlusion of the middle cerebral artery without reference to internal carotid artery changes. The clinical picture is fairly typical. The patient often suffers an apparently minor injury to the head or neck which may be either penetrating or nonpenetrating. Penetrating injuries imply an open wound, usually intraoral in children, caused by falling with a pointed object in the mouth or by tonsillectomy. There is, however, no apparent perforation of the internal carotid artery. Nonpenetrating injury need not be directly to the artery but may produce its effect by abn...