FROG: EXTERNAL FEATURES AND BODY-WALL 45 



3. The muscles of the Wrist and Fingers are numerous and 

 complicated. 



D. Muscles of the Hind-Limb. 



1. Muscles of the Thigh. 



e.g. Adductor magnus, a large muscle arising from the 

 pubis and ischium, lying on the part of the thigh, and 

 inserted into the femur near its lower end. It draws 

 the thigh towards the body. 



Sartorius, a long, narrow band arising from the lower end 

 of the ilium, lying obliquely upon the adductor magnus, 

 and inserted into the tibia on its inner side near the 

 end. It bends the knee. 



Gracilis, a large muscle arising from the ischium, lying 

 along the inner side of the adductor magnus, and in- 

 serted into the inner side of the head of the tibia. It 

 bends the knee. 



Semimembranosus, a stout muscle arising from the ischium, 

 lying on the back of the thigh, and inserted into the 

 back of the head of the tibia. It bends the knee. 

 Triceps extensor cruris, a very large muscle inserted into 

 the front of the tibia just below the head of the latter, 

 but arising from the pelvic girdle as three separate 

 muscles, the rectus femoris, vastus lateralis, and vastus 

 viedialis or crureus. All these lie on the front of the 

 thigh, and their action is to straighten the knee. 



2. Muscles of the Shank. 



e.g. Peroneus, a long muscle which arises from the end of 

 the femur, lies along the side of the tibio-fibula, and is 

 inserted into the end of the tibia and the calcaneum. 

 It straightens the leg. 



Gastrocnemius, a large, spindle-shaped muscle which forms 

 the "calf." It arises from the hinder side of the end of 

 the femur and tapers into the long tendo Achillis (or t. 

 calcaneus), which passes under the ankle joint and ends 

 in the sole of the foot. It straightens the foot on the 

 shank. 



Tibialis anterior, arising from the front of the femur by a 

 long tendon, lying in front of the shank, and dividing into 

 two bellies, which are respectively inserted into the 

 astragalus and calcaneus. It bends the foot on the 

 shank. 



3. The muscles of the Ankle and Toes are numerous and 



complicated. 



