THE LEG 351 



Peroneal Artery). This branch of the peroneal artery arises 

 in the posterior region of the leg. It pierces the interosseous 

 membrane from 35 to 50 mm. above the lateral malleolus, and 

 so enters the anterior region. There it descends upon the 

 distal part of the fibula, under cover of the peronseus tertius, 

 and its terminal branches anastomose with the lateral malleolar 

 and lateral tarsal arteries. 



Mm. Extensor Hallucis Brevis et Extensor Digitorum 

 Brevis. The short extensor of the great toe and the short 

 extensor of the toes may now be examined. They are the 

 muscles which form the fleshy cushion on the dorsum of the 

 foot. They arise together from the anterior part of the 

 dorsal surface of the calcaneus, immediately posterior to the 

 cuboid bone, and also from the stem of the cruciate ligament. 

 The common muscular mass breaks up into four segments. 

 The most medial of the four is called the short extensor of the 

 great toe. It ends in a tendon which is inserted into the base 

 of the first phalanx of the great toe. On its way from its 

 origin to its insertion it crosses the superficial surface of the 

 distal part of the dorsalis pedis artery. It is supplied by the 

 lateral branch of the deep peroneal nerve and it is an extensor 

 of the metatarso-phalangeal joint of the great toe. 



The remaining three segments of the muscular mass are 

 described collectively as the short extensor of the toes. They 

 end in tendons which join the long extensor tendons going 

 to the second, third, and fourth toes, and, by means of the 

 extensor expansion (see p. 346), they gain insertion into the 

 second and terminal phalanges of those toes. The short 

 extensor of the toes like the extensor hallucis brevis is 

 supplied by the lateral branch of the deep peroneal nerve, 

 and it acts as an extensor of the interphalangeal and metatarso- 

 phalangeal joints of the toes to which it is distributed. 



Nervus Peronseus Profundus (O.T. Anterior Tibial). The 

 deep peroneal nerve is one of the terminal branches of the 

 common peroneal nerve. It arises between the proximal 

 part of the peronaeus longus and the neck of the fibula, then 

 it pierces the anterior fibular septum and the extensor 

 digitorum longus, and so enters the anterior compartment 

 of the leg. In that compartment it descends obliquely until 

 it joins the anterior tibial vessels, a short distance distal to 

 the lateral condyle of the tibia. In the remainder of its 

 course it accompanies the anterior tibial vessels, in the first 



