THE PLANTAR NEEVES. G19 



these digital nerves ; and. opposite the ungual phalanx, each sends a dorsal branch 

 to the pulp beneath the naU, and then runs on to the ball of the toe. where it is 

 distributed like the nerves of the fingers. 



External Plantar Nerve. — The external plantar nerve completes 

 the supply of digital nerves to the toes, furnishing branches to the 

 little toe and half the fourth : it also gives a deep branch of con- 

 siderable size, "^hicli is distributed to several of the short muscles in 

 the sole of the foot. There is thus a great resemblance between the 

 distribution of this nerve in the foot and that of the ulnar nerve in 

 the hand. 



The external plantar nerve runs obliquely forwards towards the outer 

 side of the foot, along with the external plantar artery, between the 

 flexor brevis digitorum and the flexor accessorius, as far as the interval 

 between the former muscle and the abductor of the little toe. Here it 

 divides into a superficial and a deep branch, having previously furnished 

 oSsets to the flexor accessorius and the ahductor minimi digiti. 



a. The srqwrfcial iwrfion separates into two digital branches, which have the 

 same general arrangement as the digital branches of the internal plantar nerv^e. 

 They are distributed thus. 



Digital h-anchcs. — One of the digital branches continues undivided, and runs 

 along the outer side of the little toe : it is smaller than the other, and pierces the 

 plantar fascia further back. The short flexor muscle of the little toe, and occa- 

 sionally one or tivo interosseous muscles of the fourth metatarsal space receive 

 branches from this nerve. 



The larger digital branch communicates with an offset from the internal 

 plantar nerve, and bifurcates near the cleft between the fourth and fifth toes to 

 supply one side of each. 



b. The (leej) or 7nuscular branch of the external plantar neiwe dips into the sole 

 of the foot with the external plantar artery, iinder cover of the tendons of the 

 flexor muscles and the adductor poUicis, and tenninates in numerous branches 

 for the following muscles : — all the interossei (dorsal and plantar) except occa- 

 sionally one or both of those in the fourth space, the two outer lumbricales, the 

 adductor poUicis, and the transversalis pedis. 



SmniARY OF THE INTERNAL POPLITEAL ISTerve. — This ncrvc Sup- 

 plies all the muscles of the back of the leg and sole of the foot, and the 

 integument of the plantar aspect of the toes, the sole of the foot, and 

 in part that of the leg. 



External Popliteal Nerve. — This nerve descends obliquely along 

 the outer side of the popliteal space, lying close to the biceps muscle. 

 Continuing downwards over the outer part of the gastrocnemius 

 muscle (between it and the biceps) below the head of the fibula, the 

 nerve turns round that bone, passing between it and the peroneus 

 longus muscle, and then divides into the anterior tihial and the 

 muscido-cidaneous nerves. 



Lateral branches. — Some articular and cutaneous branches are 

 derived from the external popliteal nerve before its final division. 



Articular nerves. — The articular branches are conducted to the outer side of 

 the capsular ligament of the knee-joint by the upper and lower articular arteries 

 of that side. They sometimes arise together, and the upper one occasionally 

 springs from the gi-eat sciatic nerve before the bifurcation. 



From the place of division of the external popliteal nerve, a reevrrent articular 

 nerve ascends through the tibialis anticus muscle with the recuiTent artery to 

 reach the fore part of the knee-joint. 



