FIG. 83.--Superficial muscles of leg (from behind): 1, Vastus externus; 2, biceps flexor cruris; 3, semitendinosus; 4, semimembranosus; 5, gracilis; 6, sartorius; 7, outer, and 8, inner, head of gastrocnemius; 9, plantaris; 10, soleus; 11, peroneus longus; 12, peroneus brevis; 13, flexor longus digitorum; 14, tibialis posticus; 15, lower fibers of flexor longus hallucis. (Dorland’s Dictionary.)] =Muscles of the Leg.=--The greater part of the calf of the leg is formed by the _gastrocnemius_, a large bulging muscle, which rises from the condyles of the femur and is inserted along with the _soleus_, whose origin is on the back of the upper fibula, and the _plantaris_, which comes from the linea aspera, into the os calcis by a common tendon, the _tendo Achillis_, the largest and strongest tendon in the body. Its action is to extend the foot and to rotate it slightly inward. Other extensors of the foot, which also evert it, are the _peroneus longus_ and the _peroneus brevis_ at the upper and outer part of the leg, the former rising from the outer tuberosity of the tibia and the upper fibula and being inserted into the first metatarsal and the internal cuneiform, the latter arising from the lower fibula and being inserted into the fifth metatarsal. The foot is flexed, adducted, and rotated inward by means of the _tibialis anticus_, which rises from the outer tuberosity and the upper two-thirds of the outer surface of the tibia and is inserted into the internal cuneiform bone. In the foot, and corresponding to the palmar fascia in the hand, is the _plantar fascia_, the densest of all fibrous membranes. There are also various annular ligaments, and the _foot muscles_ are arranged similarly to those in the hand. =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_.