548 



APPLIED ANATOMY. 



for use in walking and to compensate for the greater length of the foot anterior to the 

 centre of motion at the ankle and its shortness posteriorly. 



The extensor group lies between the tibia and fibula anterior to the interosseous 

 membrane. The abductor group forms a mass over the fibula, and the flexor group 

 lies between the tibia and fibula on the posterior surface of the interosseous mem- 

 brane. The muscles of the calf constitute a superficial layer of muscles which end 

 below in the tendo calcaneus (Achillis). The soleus, with the two heads of the gas- 

 trocnemius, is known as the triceps surae muscle. It is absolutely essential to under- 

 stand the grouping of these muscles of the leg because thereby its construction is 

 rendered evident and their influence on distortions of the foot can be appreciated. 



FASCIA OF THE LEG. 



The deep fascia of the leg is attached above to the tubercle of the tibia, the 

 tuberosities of the tibia, and the head of the fibula. It gives off two septa from its 

 under surface, one in front separating the abductor or peroneal group from the exten- 

 sor group, and another posterior which' separates the abductor group from the soleus 

 posteriorly. This latter covers the deep flexors and separates them from the muscles 

 of the calf and is continued across to be attached to the medial (internal) edge of the 

 tibia. The deep fascia of the leg blends with the periosteum over the medial (inter- 

 nal) surface of the tibia and also with that of the lateral (external) surface of the 

 fibula in its lower fourth. At the ankle the deep fascia is continued on through 

 the annular ligaments. 



The muscles of the leg take their origin partly from these fasciae, and subsidiary 

 septa pass between the muscles. 



ARTERIES OF THE LEG. 



The leg has three main arteries, the anterior tibial, posterior tibial, and per- 

 oneal. The popliteal artery divides into the anterior and posterior tibial at the lower 



border of the popliteus muscle just below 

 the lower edge of the tibial tubercle. 



Two and a half cm. ( i in. ), or a little 

 more, below the edge of the popliteus 

 muscle the peroneal artery is given off from 

 the posterior tibial. 



The Anterior Tibial Artery. Li- 

 gation. The line of the anterior tibial 

 artery may be taken as from just internal 

 to the head of the fibula to a point on the 

 front of the ankle midway between the 

 malleoli. The anterior tibial artery pierces 

 the interosseous membrane, but the anterior 

 tibial nerve winds around the head of the 

 fibula and joins the artery 5 to 7 cm. ( 2 to 

 3 in. ) or more lower down on its outer 

 side. 



In the Upper Third. The artery lies 

 between the tibialis anterior and the exten- 

 sor longus digitorum muscles.. This inter- 

 space is better recognized by touch than by 

 sight, though a yellowish line of fat or the 

 presence of some small vessels may indi- 

 cate its position. The tendency is to make 

 the incision too close to the tibia. This 

 mistake will be avoided if the line of the artery has been marked and the incision 

 made in it. After separating the muscles, the outer edge of the tibia can be 

 felt and on the membrane close to it is the artery with venae comites to each side and 

 the nerve farther out. The needle is passed from without inward, and the veins may 



Tibialis anterior 



Anterior tibial artery . 

 Anterior tibial nerve 

 Extensor longus digitorum 



Extensor longus hallucis 



Anterior tibial artery 



Tibialis anterior 



Anterior tibial nerve 



Extensor longus digitorum 



FIG. 561. Ligation of the anterior tibial artery in its 

 upper and lower thirds. 



