PERONEAL NERVE. 479 



The PERONEAL NERVE is one half smaller than the popliteal ; it 

 passes downwards by the side of the tendon of the biceps, crossing the 

 inner head of the gastrocnemius and the origin of the soleus, to the 

 neck of the fibula, where it pierces the origin of the peroneus longus 

 muscle, and divides into two branches, the anterior tibial and mus- 

 culo-cutaneous. 



The Brandies of the peroneal nerve previously to its division are, 

 the communicans peronei, cutaneous, articular and muscular. The 

 communicans peronei, much smaller than the communicans poplitei, 

 crosses the external head of the gastrocnemius to the middle of the leg. 

 It there sends a large branch to join the communicans poplitei and con- 

 stitute the external saphenous nerve, and descends very much reduced 

 in size with the external saphenous vein to the side of the external 

 ankle, to which and to the integument of the heel it distributes fila- 

 ments. The cutaneous branch passes down the outer side of the leg, 

 supplying the integument. The articular is a small branch distributed 

 to the knee-joint. The muscular branches are twigs to the short head 

 of the biceps, peroneus longus and tibialis anticus. 



The ANTERIOR TIBIAL NERVE commences at the bifurcation of the 

 peroneal, upon the head of the fibula, and passes beneath the upper 

 part of the extensor longus digitorum, to reach the outer side of the 

 anterior tibial artery, just as that vessel has emerged through the 

 opening in the interosseous membrane. It descends the anterior 

 aspect of the leg with the artery ; lying at first to its outer side, and 

 then in front of it, and near the ankle becomes again placed to its 

 outer side. Reaching the ankle it passes beneath the annular liga- 

 ment; accompanies the dorsalis pedis artery, supplies the adjoining 

 sides of the great and second toes, and communicates with the internal 

 peroneal cutaneous nerve. 



The Brandies given off by the anterior tibial nerve are, muscular to 

 the muscles in its course, and on the foot a tarsal branch which passes 

 beneath the extensor brevis digitorum, and distributes filaments to 

 the interossei muscles and to the articulations of the tarsus and 

 metatarsus. 



The MUSCULO-CUTANEOUS nerve passes downwards in the direction 

 of the fibula, in the substance of the peroneus longus ; it then passes 

 forwards to get between the peroneus longus and brevis, and at the 

 lower third of the leg pierces the deep fascia, and divides into two 

 peroneal cutaneous branches. In its course it gives off several branches 

 to the peronei muscles. 



The Peroneal cutaneous nerves pass in front of the ankle-joint, and 

 are distributed to the integument of the foot and toes ; the external 

 supplying three toes and a half, and the internal one and a half. 

 They communicate with the saphenous and anterior tibial nerves. The 

 external saphenous nerve frequently supplies the fifth toe and the ad- 

 joining side of the fourth. 



