412 DK. C. F, SONNTAG ON THE ANATOMY, . 



internus, gemelli, quadratus femoiis, biceps, and gluteus maxi- 

 mus. As it courses round tlie tuber ischii and down the thigh 

 it gives branches to the hamstrings. In the popliteal space 

 it divides into external and internal popliteal nerves. The 

 external popliteal nerve passes tinder the biceps a,nd through the 

 extensor longus digitorum and supplies both. It is continued as 

 the anterior tibial nerve. The latter supplies the £i,nterior 

 tibial muscles at the top, the ankle joint, the flexor brevis 

 digitorum, the tarso -metatarsal joints and the skin of the 

 adjacent sides of the hallux and index. It gives off the 

 7m(,sculo-cuta,neous nerve which, however, only supplies the skin 

 of the adjacent sides of the index, medius, annularis, and 

 minimus. No nervus suralis exists. The internal popliteal 

 nerve becomes the posterior tibial nerve. This passes between 

 the heads of the gastrocnemius and supplies them. As it passes 

 down the leg it gives a branch to the upper part of the anterior 

 tibial muscles and branches to the posterior tibial muscles, 

 peronei, aiikle joint, and flexor brevis digitorum. It divides 

 into three terminal branches. A muscular branch runs to the 

 abductor minimi digiti. The internal plantar nerve, or second 

 terminal branch supplies the abductor hallucis, lumbricales, 

 flexor brevis hallucis, adductor hallucis, joints of the foot, and 

 the skin of the inner four toes. The nerve to the last digit 

 communicates with the lateral plantar nei-ve. The lateral plantar 

 nerve, or third terminal branch divides into superficial and deep 

 parts. The former supplies the abductor and flexor and skin on 

 the outer side of the fifth toe. The latter supplies the adductor 

 hallucis, interossei, and tarso-metatarsal joints. 



The superior gluteal tierve (S.G.N) emerges above the 

 pyriformis, and divides into two branches which follow those of 

 the artery. A special branch runs to the gluteus minimus, but 

 the scansorius is supplied by the sciatic nerve. 



The inferior gluteal nerve (I.G N) accompanies the corre- 

 sponding artery to the gluteus maximus. 



The pudendal nerve (Pud.N), after emerging through the 

 sciatic notch, forms a prominent cord lying alongside the 

 pudendal vessels. It lies in the outer wall of the ischio-rectal 

 fossa, but no well-marked Alcock's canal exists. It gives 

 several twigs to the rectum, external sphincter ani, levator ani, 

 sphincter vaginse, and ischio-cavernosus. It also supplies the skin 

 of the perineal region. It differs from that in Man in that it 

 does not pierce any triangular ligament, and it has no branches 

 to the transverse perineal muscles, for the latter are absent. It 

 does not divide into two terminal branches of large size. 



The small sciatic nerve (S.S.N) courses much as in Man. 



I agree with Bolk (7) that the Chimpanzee, like the other 

 Anthropoids, differs from Man in the absence of a nervus 

 suralis. 



The lumbar and sacral nerves receive grey rami communicantes 

 from the gangliated cords of the sympathetic nerves (text-fig. 46). 



