818 



THE NERVOUS SYSTEM 



gastrocnemius, plantaris, and soleus muscles, and b}' the intermuscular part of the 

 cleep fascia of the leg. Lower down, as it approaches the ankle, it is covered only 

 Ijy the skin and fasciie. Its anterior relations are the tibialis posticus in the upper 

 and the flexor longus digitorum and the tibia in the lower portion of its cours(\ 

 The posterior til )ial vessels are i)laced externally to its upper part; alcove the middle 

 of the leg they cross in front of the nerve, and run downwards jiarallel to its inner 

 side. 



Branches. — The posterior tibial nerve supplies the three deep muscles of the 



Fig. 469. — Superficial Nerves in the Sole of the Foot. i^Ellis.) 



Abduetor hallueis 



Flexor brevis digitorum 



INTERNAL PLANTAR 

 NERVE 



Internal plantar artery 



BRANCH OF INTER- 

 NAL PLANTAR 

 NERVE TO INNER 

 SIDE OF HALLUX 



Abduetor minimi digiti 



Exiernal plantar artery 



EXTERNAL PLANTAR 

 NER VE 



DIGITAL COLLATERAL 

 BRANCHES OF EX- 

 TERNAL PLANTAR 



DIGITAL COLLATERAL 

 BRANCHES OF INTER- 

 NAL PLANTAR 



I 



calf, viz. the tibialis jy^-'^tic^'^, flexor longus digitorum, and flexor longus hallueis, the 

 two former V)y twigs from the fifth lumbar and the first sacral nerves, whilst the 

 latter receives additional fibres from tlic second sacral nerve, and it gives a l)ranch 

 to the soleus. It also furnishes one or two articular filament^s to the ankle-joint, 

 and gives off a cutaneous branch, the internal calcancan. 



(1) The internal calcanean or calcaneo-plantar cutaneous branch contains 

 fibres from the first and second sacral nerves. It arises from the posterior til>ial 

 nerve a little above the level of the inner malleolus, and passes under cover of the 

 internal annular lisfament. where it divides into several branches. These branches 



