224 ELEMENTS OF MAMMALIAN ANATOMY. 



lumbar region and its caudal branch is distributed 

 to the superficial structures of the inguinal region. The 

 fourth lumbar nerve divides into two parts, one of which 

 is the external cutaneous nerve, supplying the skin and 

 other structures of the hip region, and the other is the 

 external spermatic, supplying the external genital organs. 



The anterior crural nerve is composed mainly of branches 

 of the fifth and sixth lumbar. It receives a small branch 

 from the fourth. It supplies the psoas muscles, which 

 it pierces, and then divides into several branches, one 

 of which is the saphenous, passing subcutaneously along 

 the mesal aspect of the leg. The other nerves supply 

 the muscles of the thigh on the cephalic and mesal 

 aspect. The obturator nerve is composed of branches 

 from the sixth and seventh lumbar. It is smaller than 

 the preceding, and passes through the obturator foramen 

 to supply the obturator and adductor muscles. 



The great sciatic nerve is composed mainly of the 

 ventral branches of the seventh lumbar and first sacral 

 nerves. It usually receives accessions from the other 

 sacral nerves and the sixth lumbar. The great sciatic 

 is the largest peripheral nerve in the body. It passes 

 caudad from its origin around the greater sciatic notch 

 and thence along the caudal aspect of the thigh to the 

 popliteal space, where it divides into the internal and 

 external popliteal nerves. The former continues down 

 the caudal side of the tibia as the posterior tibial nerve 

 to the internal malleolus, where it divides into internal 

 and external plantar nerves, which supply the digits. 

 The external popliteal or peroneal nerve extends to 

 the outer cephalic aspect of the leg, where it divides 

 into the musculocutaneous and anterior tibial nerves. The 

 former extends between the extensor longus digitorum 

 and peronei muscles to its ramification on the dorsum 



