“…Occlusion of a carotid artery, as in case 1, is a known complication of percutaneous carotid angiography (Abbott, Gay, and Goodall, 1952;Baker, 1960;Lindner, Hardy, Thomas, and Gurdjian, 1962) but is in our experience a very rare occurrence. Traumatic occlusion of the internal carotid artery (case 2) is also well documented (Clarke, Dickson, and Smith, 1955;Murray, 1957;Gurdjian, Hardy, Lindner, and Thomas, 1963;Houck, Jackson, Odom, and Young, 1964;Toakley and McCaffrey, 1965) but of particular interest in the present case was the finding on histological examination of a haematoma between the medial and adventitial coats of the artery. Case 3 suffered from systemic lupus erythematosus, another known cause of arterial thrombosis (Dubois, Commons, Starr, Stein, and Morrison, 1952;Murphy, 1954).…”