THE LOWER LIMB 515 



plantar venous plexus which turn round the outer border of the 

 foot, it passes below and behind the external malleolus, and 

 thus reaches the back of the leg. It then passes upwards and 

 inwards, lying at first to the outer side of the tendo Achillis. On 

 reaching the middle line of the calf, it ascends in the groove between 

 the two heads of the gastrocnemius until it arrives at the interval 

 between the condyles of the femur. Up to this point the vein is 

 superficial to the deep fascia. It now, however, passes through 

 an opening in that fascia, and terminates in the pophteal vein. 

 As high as the centre of the calf the vein is accompanied by the 

 short saphenous nerve, which Ues on its outer side. From the 

 centre of the calf up to where the vein pierces the deep fascia it 

 is accompanied by the terminal part of the small sciatic nerve and 

 the middle superficial or cutaneous sural artery. It receives 

 many tributaries from the calcaneal region, and from the outer 

 and back parts of the leg, and it communicates at intervals with 

 the venae comites of the posterior tibial and peroneal arteries. 

 Just before it pierces the deep fascia a communicating branch 

 passes upwards and inwards from it to join the long saphenous 

 vein. The external or short saphenous vein is provided with about 

 ten valves. 



External Aspect of the Leg. 



In this region the lateral cutaneous branch of the external pop- 

 liteal nerve is met with. It supplies the integument of the outer 

 side of the leg over about its upper two- thirds, as well as the adjacent 

 integument of the sural region. 



Muscles. Peroneus Longus — Origin. — (i) The external aspect 

 of the head of the fibula ; (2) the adjacent part of the external 

 tuberosity of the tibia ; (3) the upper two-thirds of the external 

 surface of the shaft of the fibula ; (4) the "antero-external and 

 postero- external intermuscular septa; and (5) the deep fascia. 



Insertion. — ^The tendon of insertion divides into two parts. The 

 main part is inserted into the outer side of the tuberosity on the 

 plantar surface of the base of the first metatarsal bone, and the other 

 into the lower and anterior part of the outer surface of the internal 

 cuneiform bone. 



Nerve-supply. — ^The musculo-cutaneous nerv^e. 



Action. — (i) To extend the foot upon the leg ; (2) to abduct or 

 turn out the fore part of the foot ; (3) to depress the inner border 

 of the foot, the efiect of which is to raise the outer border and 

 produce eversion of the sole ; and (4) to support and strengthen 

 the transverse arch of the foot. 



The tendon descends behind that of the peroneus brevis, and, 

 ; along with it, passes through the groove behind the external mal- 

 leolus and beneath the external annular Ugament, the two tendons 

 ' having one synovial sheath in common. After leaving the malleolar 

 groove, the tendon passes forwards on the outer surface of the os 



