514 



NEUHOLOGY. 



two important braoches, the external popliteal and external 

 saphenic nerves. 



The External Popliteal nerve leaves the great sciatic 

 about the level of the geraelli muscles. It passes between the 

 adductor magnus and gastrocnemius, and arrives at the supe- 

 rior extremity of the leg, behind the lateral ligament of the 

 femoro-tibial articulation, when it terminates in two branches; 

 one, the anterior tibial nerve, is short, and enters the muscles 

 attached to the superior extremity of the anterior face of the 

 tibia, in which it ramifies ; the other the rausculo-cvianecnis 

 nerve turns downwards by the outer side of 

 the anterior surface of the leg, and, passing 

 the hock, metatarsal bone, and fetlock, 

 terminates at the pastern. It gives off 

 numerous muscular and cutaneous filaments. 

 The External Saphenic nerve is given 

 off shortly before the great sciatic enters the 

 gastrocnemius muscle, descending under 

 the fascia which covers the latter, and 

 accompanying the external saphenic vein. 

 It passes the tarsal joint, and ramifies on 

 the external aspect of the metatarsus, some 

 of its filaments reaching the digital region. 

 In addition to the above, a small nerve 

 is given off from the great sciatic to supply 

 the ischio-femoralis, gemelli, and obturator 

 intern us ; also a large branch, the posterior 

 crural, aris3S as the sciatic nerve bends 

 downwards over the femur, and supplies the 

 muscles of the lateral and posterior femoral 

 regions. A fasciculus of nerves, given off as 

 the sciatic enters the gastrocnemii, assists in 

 supplying the posterior tibial group -^i jauscles. 

 The External and Internal Metatarsal InERves, formed 

 by the bifurcation of the great sciatic, pass down the side of the 

 flexor tendons, and terminate as the digital nerves. Towards the 

 superior extremity of the cannon bone, the external metatajrsai 

 nerve is earned outwards between the splint bone and the tendon, 

 while the internal one is placed on the inner side of the tendon, 

 and foUows the posterior border of the inner splint. The digiiui 

 nerves are distributed in a similar manner to those of the fore foot. 



Pio. 193. 

 Tarsal and metatarsal nerves 

 —internal aspect. <r, Internal 

 cutaneous branch ; I, External 

 metatarsal ; c, Internal meta- 

 tarsal; (I, Their counectins 

 branch ; e. Internal digital. 



