Aneurysms constitute uncommon sequelae of injuries to the thoracic outlet. Most such aneurysms are secondary to blunt trauma and usually involve the great vessels at their take-off from the aortic arch. Penetrating injuries are more often identified in the more distal vessels and only very rarely present as pseudoaneurysms. Reported here is a single case of a chronic posttraumatic pseudoaneurysm arising from both the right common carotid artery and the right subclavian artery. The workup and surgical approach provide practical lessons, complemented with illustrations that aid in the understanding of the case. It is an unusual case because of the dual-inflow nature of the aneurysm.