all 



: 



BACK OP THE LEG. 243 



in its course numerous muscular branches, some of which 

 were divided in removing the superficial layer of muscles; 

 others will be seen going to the deep layer ; a nutrient artery, 

 to the tibia, may sometimes be found, if the subject is well 

 injected. The principal branch of the posterior tibial artery 

 is the peroneal. 



The peroneal artery arises some distance from the com- 

 mencement of the posterior tibial, and passes downward 

 along the inner border of the fibula; in the lower third of 

 the leg it divides into two branches: one of them, the 

 anterior, perforates the interosseous membrane, and is dis- 

 tributed in front of the external malleolus; the posterior 

 division continues downward to the outside of the os calcis, 

 where it breaks up into external calcanear branches. The 

 peroneal and posterior tibial arteries present frequent varia- 

 tions of distribution arid size ; one or the other is occasion- 

 ally absent, and they sometimes communicate with each 

 ther by means of a short, though large, transverse anas- 



mosis. 



The posterior tibial nerve accompanies the posterior 

 ibial artery, lying first upon its inside, and then upon its 

 outside. At the inner malleolus, it divides into two 

 branches, the internal and external plantar. In its course, 

 it gives off muscular branches, one of which accompanies 

 the peroneal artery ; at the heel, it gives off the plantar 

 cutaneous branches, distributed to the integument of the 

 side of the heel. 



The POPLITEUS is a short muscle situated just below the 

 knee-joint; arising from the outer side of the external con- 

 dyle, it passes obliquely downward, to be inserted into 

 the surface of the tibia, above the oblique line, known as 

 the popliteal. 



The FLEXOR LONGUS DIGITORTJM PEDIS arises from the sur- 

 face of the tibia, below the popliteus muscle, and passing 

 behind 'the internal malleolus, through a sheath in the 

 internal annular ligament, between the tendons of the 

 tibialis posticus and the flexor longus pollicis, enters the 

 sole of the foot, and divides into four tendons, inserted 

 into the last phalanges of all the toes, except the great toe, 

 as will be seen hereafter. 



The FLEXOR LONGUS POLLICIS PEDIS lies upon the outer 

 side of the leg, and arises from the lower two thirds of the 

 fibula, and from the interosseous membrane; its tendon 

 curves around the internal malleolus, passes through a 



