Chap. 13.] the Leg, &(. \ 169 



tuberofity of the ifchium, and is inferted into the inner 

 and back part of the head of the tibia. It bends the 

 leg, and brings it directly backwards. 



The biceps flexor cruris arifes by two diftincl: heads, 

 Of thefe the longer proceeds from the tuberofity of the 

 ifchium, and the Ihorter from the linea afpera, a little 

 below the termination of the gluteus maximus. The 

 two heads join a little above the external condyl of the 

 os femoris, and are inferted by a ftrong tendon into the 

 head of the fibula, forming the external ham -firing. 

 The internal is formed by the two preceding mufcles. 



The popliteus arifes from the lower and back part 

 of the external condyl of the os femoris, it runs over 

 the ligament which involves the joint, and is inferted 

 into a ridge at the upper and internal edge of the tibia, 

 a little below its head. It affifts in bending the 

 leg, and prevents the capfular ligament from being 

 pinched. 



The mufcles fituated on the leg, and which per- 

 form the motions of the foot, are either extenfors or 

 flexors of the foot, or extenfors and flexors of the 

 toes in general. 



The extenfors of the foot are : the gaftrocnemius, 

 which arifes by two heads, ope from each of the con- 

 dyls of the os femoris. A little below the joint their 

 flemy bellies unite in a middle tendon, and below 

 the middle of the tibia it terminates in a broad tendon 

 jof the following mufcle. 



The ibleus, or gaftrocnemius internus, alfo arifes by 

 two heads; one from the upper and back .part of the head 

 of the fibula, the other from the upper and pofterior part 

 of the tibia. The fiefh of this mufcle, covered by the 

 tendon of the gemellus, runs down nearly as far as the 

 extremity of the tibia, a little above which the tendons 

 pf this and of \he preceding mufcle unite, forming a 



ftrong 



