DEEP VENOUS thrombosis of the upper extremities accounts for a small percentage of the total cases of vein thrombosis throughout the body. Ochsner et al1 reviewed 1,233 cases of acute thrombophlebitis and found the upper-extremity deep veins involved in only 2%, while Barker et al,2 reporting on 584 cases of deepvein thrombosis, found the upper extremities involved in only 24. The low incidence has been explained by the rapid emptying of the venous system in the upper limbs by the frequent movements of the arms and by the shorter course through which the blood must flow in its return to the heart. When it occurs, it is usually associated with congestive heart failure, often as a terminal event, or with carcinoma, either from metastases to the axilla or from direct compression of the great veins by mediastinal or pulmonary tumors. Separate from the above causes is thrombosis of