THE LOWER LIMB 



503 



Musculo- 

 cutaneous i 



Anterior Aspect of the Leg and Dorsum of the Foot 



Musculo-cutaneous Nerve (Superficial Peroneal). — This nerve is 

 one of the terminal branches of the external popliteal, arising from 

 that nerve on the outer side of the neck of the fibula, where it lies 

 between the bone and the peroneus longus. It then descends in the 

 antero-external intermuscular septum, lying between the extensor 

 longus digitorum in front, and the peroneus longus and peroneus 

 brevis behind. When it reaches the junction of the upper two- 

 thirds and lower third of the leg, it becomes cutaneous by piercing 

 the deep fascia, and almost immediately afterwards it divides into 

 its two terminal branches, internal and 

 external. 



Branches. — The branches of the 

 nerve are as follows : muscular to the 

 peroneus longus and peroneus brevis ; 

 and cutaneous to the integument of the 

 front of the leg in its lower third, 

 which arises as soon as the nerve 

 pierces the deep fascia. 



The internal terminal branch 

 descends to the dorsum of the foot, 

 lying superficial to both divisions 

 of the anterior annular hgament. It 

 then divides into two branches, inner 

 and outer. The inner branch supplies 

 twigs to the integument of the internal 

 malleolus and inner side of the foot, 

 which communicate with the terminal 

 part of the long saphenous nerve, and 

 it then becomes the dorsal digital 

 nerve of the inner side of the great 

 toe. It gives a communicating branch 

 to the dorsalis pedis nerve as that 

 lies upon the first dorsal interosseous 

 muscle. The outer branch passes to the cleft between the second 

 and third toes, where it divides into two dorsal collateral digital 

 nerves for the supply of the contiguous sides of these toes. 



The external terminal branch, like the internal, descends to 

 the dorsum of the foot, and also lies superficial to both divisions 

 of the anterior annular ligament. On the dorsum of the foot it 

 divides into two branches, inner and outer. The inner branch 

 passes to the cleft between the third and fourth toes, and the 

 Older to the cleft between the fourth and fifth toes. At these 

 clefts the inner and outer branches divide each into two dorsal 

 collateral digital nerves for the supply of the contiguous sides of 

 the third and fourth, and fourth and fifth toes. The outer 

 branch in its course supplies twigs to the integument of the 



Fig. 243.— ^Diagram of the 



Nerves of the Foot 

 (Dorsal Aspect). 



