Figure 15-15. The blood supply to the head and neck of the femur. Apart from a small branch of the obturator artery that enters through the ligament of the head, most of the epiphysis of the head is supplied by diaphysial branches from the lateral and medial circumflex arteries of the femoral artery. These branches travel in retinacula, i.e., reflections of the capsule along the neck toward the head. The vessels may be damaged in fractures of the neck of the femur, which may result in avascular necrosis of the head of the bone. (Based on von Lanz and Wachsmuth.) Click for high resolution image.