DISSECTION OF THE DOG 



91 



n. tibialis — 

 m, semUendinosus. 



M. EXTENSOR DIGITORUM BEEVis. — The short extensor of the digits is 

 confined to the dorsum of the pes. Its three heads arise from the calcaneus 

 and the anterior hgament of the tarsus. Of its three tendons, the most 

 lateral goes to the fourth 



digit ; the middle one to the m. semimemhramsm- 



third and fourth digits ; and 

 the medial tendon to the 

 second and third digits. 

 Their union with the tendons 

 of the long extensor is 

 blended with the tendons of 

 the interosseous muscles. 



M. EXTENSOR HALLTJCIS 



LONGTTS. — This is a thin 

 muscle arising from the 

 lateral surface of the fibula 

 about the junction of the 

 proximal and middle thirds. 

 It lies, at first, between the 

 long extensor and the tibia, 

 then between the anterior 

 tibial and the long extensor 

 muscles, and has a variable 

 insertion. It may end on 

 the rudimentary first meta- 

 tarsal bone. 



m, gastrocnemiu. 



v. saphena parva - 



m. plantaris . ^ 



m, abdncior digiii- 

 quirdi 



^^m. vastus lateralis 



—n. peronceus 

 communis 



m. tibialis anterior 



m. peronceus longus 



~--m. flexor hallucis longus 



.m. extensor digitorum longus 



m. peroncEjts brevis 



m. extensor digitorum brevis 



Dissection. — The dissec- 

 tion of the common 

 peroneal nerve and its 

 branches and the an- 

 terior tibial vessels will 

 be facilitated by the 

 reflection of the long 

 peroneal muscle. The 

 muscle should be cut 

 across about the mid- 

 dle of its fleshy belly. 



To follow the deep peroneal nerve and the anterior tibial artery, it is 



necessary to reflect the short extensor muscle also. 



N. j-BRO^JEVS COMMUNIS.— The common peroneal nerve is the smaller of 



the two terminal branches of the sciatic. Beginning about the middle of 



the thigh, it crosses the gastrocnemius and deep flexor of the digit under 



Fig. 36. — Dissection of the lateral aspect of the leg 



