92 DISSECTION OF THE DOG 



cover of the biceps muscle. Disappearing betAveen the long peroneal and deep 

 flexor muscles, it divides in the proximal half of the leg into deep and superficial 

 branches (n. peronaeus profundus et n. peronajus superficialis) . 



Before its division the common peroneal nerve supplies a branch to the 

 long peroneal muscle. 



N. PERONyEUS SUPERFICIALIS. — Tlie Superficial branch of the common 

 peroneal nerve is included for a time in the septum between the peroneeus 

 longus and the extensor digiti quinti muscles. Piercing the deep fascia over 

 the lateral aspect of the leg some little distance proximal to the tarsus, it becomes 

 subcutaneous, and has been followed over the dorsum of the pes where it suppHes 

 a dorsal cutaneous nerve of the first digit, and the second, third, and fourth com- 

 mon dorsal digital nerves distributed to the second, third, fourth, and fifth digits. 



While still deep to the fascia of the leg, the superficial peroneal nerve 

 furnishes branches to the extensor digitorum longus, peronaeus brevis, and 

 extensor digiti quinti muscles. 



N. PERONiEus PROFUNDUS. — From the point at which it leaves the common 

 peroneal nerve, the deep peroneal branch runs obliquely between the peronaeus 

 longus on the one hand, and the extensor digiti quinti and deep fiexor of the 

 digit on the other. Thus the nerve comes into contact with the anterior tibial 

 artery, alongside which and its continuation (the a. dorsalis pedis) it runs very 

 obHquely across the front of the tibia to the fiexor aspect of the tarsus, where 

 it terminates in a medial and a lateral branch. The medial branch follows 

 the a. dorsalis pedis until that vessel disappears from the region, and then 

 follows the groove between the second and third metatarsal bones to form 

 the n. metatarsei dorsalis II. The lateral branch crosses the tarsus under 

 cover of m. extensor digitorum brevis, which it supplies, and then furnishes 

 the nn. metatarsei dorsales III et IV. 



While in the leg, the deep peroneal nerve contributes branches to the 

 peronaeus longus, extensor digitorum longus, tibialis anterior, and extensor 

 hallucis longus muscles. 



A. TIBIALIS ANTERIOR. — The anterior tibial artery is practically the con- 

 tinuation of the popliteal artery. By piercing the interosseous membrane 

 between the tibia and the fibula, the artery gains the lateral surface of the 

 former bone, along which it runs, with some degree of obliquity, towards the 

 tarsus. The peronaeus longus, extensor digitorum longus, extensor hallucis 

 longus, and tibiahs anterior muscles cover the artery in succession. 



Opposite the joint between the tibia and the talus, the anterior tibial artery 

 changes its name to that of dorsal artery of the pes (a. dorsahs pedis), which 

 crosses the flexor aspect of the tarsus, between the tendons of the anterior 

 tibial and long extensor muscles, to disappear into the space between the 

 bases of the second and third metatarsal bones. Before disappearing, the 

 a. dorsalis pedis supplies the second, third and fourth dorsal metatarsal arteries 

 (aa. metatarseae dorsales II, III, et IV). 



