The Blood Supply of the Lower Extremity.—The blood supply of the lower extremity comes from the external iliac artery, a branch of the common iliac, which passes obliquely downward and outward along the border of the psoas muscle to Poupart’s ligament, where it enters the thigh and becomes the femoral artery. Its only important branches are the deep epigastric, which goes up along the internal abdominal ring, and the deep circumflex iliac. As the femoral artery it passes down the inner side of the thigh to the internal condyle of the femur, being very superficial at Scarpa’s triangle, where it can be compressed with the thumb to stop hemorrhage below. If a tourniquet is applied, it should be applied a little lower down. The first and most important branch of the femoral is the profunda femoris.

About two-thirds of the way to the knee the artery takes the name popliteal. It lies superficially in the popliteal space back of the knee, but above and below it is covered with muscles. Its branches supply the knee-joint and nearby muscles and are unimportant. At the lower border of the popliteus muscle, a small muscle at the knee, it divides into the anterior and posterior tibial arteries. The course of the former of these may be marked by a line from the inner side of the head of the fibula to midway between the malleoli at the front of the ankle, where it terminates in the dorsalis pedis artery for the back of the foot. By this last the pulse is sometimes taken and its pulsation is a guide in determining how high up to amputate in gangrene of the foot. The posterior tibial extends obliquely down the back of the leg to the heel, where it divides into the internal and external plantar arteries which go to the sole of the foot. Its most important branch is the peroneal.

Besides the deep veins accompanying the arteries there are the superficial veins, the internal or long saphenous on the inner side of the leg and thigh and the external or short saphenous on the middle of the leg posteriorly and emptying into the popliteal vein. Varicosity often occurs in these veins.

Nerves.—The nerves of the muscles about the hip are branches of the lumbar nerve. The anterior crural supplies the anterior part of the thigh, the gluteal the muscles of the same name, and the great sciatic the large muscles of the back of the thigh. Below the knee the anterior tibial goes to the tibialis anticus and the internal popliteal to the muscles of the calf, while the peroneus muscles are supplied by the musculo-cutaneous.


[INDEX.]


SAUNDERS’ BOOKS FOR NURSES