660 



SPINAL NERYES. 



Fig. 359. The Plantar Nerves. 



opposite the knee-joint, it is in close relation with the vessels, and crosses the 

 artery to its inner side. 



The branches of this nerve are articular, muscular, and a cutaneous branch, 

 the external or short saphenous nerve. 



The articular branches, usually three in number, supply the knee-joint; two 

 of these branches accompany the superior and inferior internal articular arteries ; 

 and a third, the azygos. 



The muscular branches, four or five in number, arise from the nerve as it lies 

 between the two heads of the Gastrocnemius muscle; they supply that muscle, 

 the Plantaris, Soleus, and Popliteus. 



The external or short saphenous nerve (Fig. 357) descends between the two 

 heads of the Gastrocnemius muscle, and, about the middle of the back of the 

 leg, pierces the deep fascia, and receives a communicating branch (communicans 

 peronei) from the external popliteal nerve. The nerve then continues its course 

 down the leg near the outer margin of the tendo Achillis, in company with the 

 external saphenous vein, winds round the outer malleolus, and is distributed to 

 the integument along the outer side of the foot and little toe, communicating 

 on the dorsum of the foot with the musculo-cutaneous nerve. 



The posterior tibial nerve (Fig. 358) commences at the lower border of the Pop- 

 liteus muscle, and passes along the back part of the leg with the posterior 



tibial vessels to the interval between the 

 inner malleolus and the heel, where it divides 

 into the external and internal plantar nerves. 

 It lies upon the deep muscles of the leg, and 

 is covered by the deep fascia, the superficial 

 muscles, and integument. In the upper part 

 of its course, it lies to the inner side of the 

 posterior tibial artery; but it soon crosses 

 that vessel, and lies to its outer side as far 

 as the ankle. In the lower third of the leg, 

 it is placed parallel with the inner margin of 

 the tendo Achillis. 



The branches of the posterior tibial nerve 

 are the muscular and plantar cutaneous. 



The muscular branches arise either sepa- 

 rately or by a common trunk from the upper 

 part of the nerve. They supply the Tibialis 

 Posticus, Flexor Longus Digitorum, and 

 Flexor Longus Pollicis muscles ; the branch 

 to the latter muscle accompanying the pero- 

 neal artery. 



The plantar cutaneous branch perforates the 

 internal annular ligament, and supplies the 

 integument of the heel and inner side of the 

 sole of the foot. 



The internal plantar nerve (Fig. 359), the 

 larger of the two terminal branches of the 

 posterior tibial, accompanies the internal 

 plantar artery along the inner side of the 

 foot. From its origin at the inner ankle it 

 passes forwards between the Abductor Pollicis and Flexor Brevis Digitorum, 

 divides opposite the bases of the metatarsal bones into four digital branches, 

 and communicates with the external plantar nerve. 



Branches. In its course, the internal plantar nerve gives off cutaneous 

 branches, which pierce the plantar fascia, and supply the integument of the 

 sole of the foot; muscular branches, which supply the Abductor Pollicis and 

 Flexor Brevis Digitorum ; articular branches to the articulations of the tarsus 



