424 PERONEAL NERVE. 



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 

 musculo-cutaneous. 



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

 the communicans peronei, cutaneous, and muscular. The commu- 

 nicans 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 

 constitute the external saphenous nerve, and descends very much 

 reduced in size by the side of the external saphenous vein to the 

 side of the external ankle, to which and to the integument of the 

 heel it distributes filaments. The cutaneous branch descends in the 

 integument upon the outer side of the leg, in which it ramifies. 

 The muscular branches proceed from near the termination of the 

 peroneal nerve ; they are distributed to the upper part of the tibialis 

 anticus. 



The interior 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 ; it accompanies the dorsalis pedis artery, supplies the adjoin- 

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

 internal peroneal cutaneous nerve. 



The Branches 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 fila- 

 ments 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 of the toes ; 

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

 and a half. They communicate with the saphenous and anterior 

 tibial nerve. The external saphenous nerve frequently supplies the 

 fifth toe and the adjoining side of the fourth. 





