NEUROLOGY 287 



largest branch (Fig. 69, No. 14) passes with the tendon of the ilio- 

 fibularis, or biceps femoris muscle, through a loop, the biceps band, 

 and lies on the upper lateral surface of the fibula. It is covered 

 by the external head of the gastrocnemius muscle. It innervates 

 the three posterior muscles of the lower thigh, and then divides into 

 two branches. One, the superficialis peroneus (Fig. 69, No. 16) 

 passes with the profundus nerve, forming a double trunk and 

 occupying the tibio-fibular groove on the antero-lateral side. It 

 passes over the transverse ligament and the tibio-metatarsal joint, 

 and after sending small branches to the structures of the tibial 

 side of the metatarsus, it ends as a cutaneous nerve on the upper 

 side of the third and the fourth toe. 



The other branch is the peroneus profundus, which separates from 

 the peroneus superficialis and passes downward in company with 

 the tendons, under the transverse ligament, and then along the 

 anterior upper surface of the metatarsus, where it innervates the 

 muscles of that region. It gives branches to the malleolus, to the 

 tendons of the third toe, and to the median part of the second toe, 

 and supplies the cutaneous structures of the third and the fourth toe. 



The third branch of the ischiadica, a long nerve, is given off just 

 after the ischiadica passes through the loop. It passes downward 

 between the two peroneal nerves. It is covered by a sheath. It 

 passes over the posterior outside rim of the intertarsal joint and 

 innervates the tendon sheath. The main portion of this nerve is 

 located on the anterior surface of the tendon Achillis, and passes 

 down on the plantar side, and innervates the periosteum and all 

 plantar foot muscles. It finally radiates to the plantar surface of 

 the three anterior toes. 



The integument of the toes is sparingly supplied with nerves. 



The nerve trunks that do not pass through the biceps band, or 

 loop can be divided into a medial (Fig. 69, No. 15) and a lateral 

 (Fig. 69, No. 17) portion. The medial portion (Fig. 69, No. 15) 

 soon divides into numerous branches which supply the muscles 

 of the posterior and the inner portion of the thigh. A rather large, 

 long branch passes downward along the tendon of the plantar mus- 

 cle, which lies on the posterior median edge of the tibia, and gives 

 off twigs to the median and posterior part of the intertarsal joint, 

 supplying the periosteum and other structures and the adjacent 

 skin. It passes downward along the outer side of the medial meta- 

 tarsal insertion of the tendon Achillis. 



