FEMORAL AND SCIATIC NERVES 377 



the tibia and fibula, and their tendons all pass in front of the 

 ankle-joint to flex it (dorsal flexion). The lateral side of the leg is 

 occupied by the peroneus longus and brevis whose tendons pass 

 behind the lateral malleolus to extend the foot. They are ac- 

 companied by the superficial peroneal nerve which supplies them 

 (ant. tibial nerve). 



The long tendons for the toes are plainly visible on the dorsum 

 or top of the foot, and also those of the short flexor, which has four 

 tendons belonging to the four medial toes. 



Posterior. The calf muscles, which lift the heel, completely 

 cover the deep muscles whose tendons pass into the sole of the foot 

 behind the medial malleolus to extend the foot. 



The deep, or posterior tibial muscles, lie between tibia and fibula 

 bound down by the deep transverse fascia of the leg. 



The large nerves for the lower extremity are the femoral and 

 the sciatic. 



The femoral comes under the inguinal ligament into Scarpa's 

 triangle and immediately breaks up into branches which supply 

 the structures of the thigh, the long saphenous nerve being the 

 only branch to go below the knee. It runs all the way to the 

 medial border of the foot. 



The sciatic comes through the great sciatic notch, descending 

 between the great trochanter and the tuber of the ischium into 

 the back of the thigh, to divide at the popliteal space into the 

 tibial and the common peroneal nerves. The tibial nerve continues 

 under the calf muscles and into the plantar region. The peroneal 

 nerve winds around the head of the tibia to the front of the 

 leg, sending the deep peroneal branch to the anterior muscles, and 

 dorsum of the foot. 



LOCATION OF LARGE VESSELS AND NERVES IN THE 

 EXTREMITIES 



The vessels and nerves are so placed as to be in the least 

 possible danger from pressure or blows. For example, the axillary 

 vessels and brachial plexus are deep in the axilla; the brachial 

 vessels and median and ulnar nerves are on the least exposed side 

 of the arm, and they pass in front of the elbow-joint where the 

 motion of the joint will not interfere with them. So in the fore- 



