MUSCLES i iF TIIK HIND LIMB. 



103 



Fig. 86. 



internally in a concave apouenrotic arch : the second head is a thin, 

 tendinous slip, arising from the common tendon of the triceps as 

 this lies on the knee-joint. The muscle is thickest near its origin, 

 and then gradually diminishes in size as it passes backwards; the 

 superficial surface is convex, the deep surface is flat. By tracing the 

 tendons of origin, they are seen soon to unite and form a common 

 flat tendinous surface, broad in front, 

 contracted behind; this aponeurosis 

 lies in a plane running ' obliquely 

 from the deep surface towards the 

 superficial surface, without, how- 

 ever, reaching this. The muscular 

 fibres arise from both surfaces of the 

 aponeurosis, the fibres of the two 

 sides diverging slightly as they pass 

 backwards so as to be inclined at a 

 small angle to each other. The 

 fibres are inserted into a fibrous ex- 

 pansion (Ajj) which lies on the su- 

 perficial surface of the muscle; thin 

 and slight in front, this aponeurosis 

 rapidly thickens posteriorly until it 

 passes into the tendo Achilti*. 



128. M. til'iali* pozticus (Fig. 

 86 t.jj.). 



Duges, cruro-astragalien, n. 160. 



Covered by the geutrocnemiw this 



Muscles of the right leg and foot of Rana etculenla. 

 Dorsal view. 



aji. M. abductor hallncis. 



a.li M. abductor longus digit! L 



A. p. Aponeurosis plantaris. 



b M. biceps. 



f.t. M. extensor tarsi. 



FJ. M. flexor diaitorum III, IV. V longus. 



t'.l'. M. flexor digitorum I and II longus. 



./ M. gastrocnemius, drawn towards the right. 



</ Tendon of origin of gastrocnemius. 



/.f. Ligamentum calcanei. 



M. plantaris. 



f.i. MM. internus maior and minor. 



.'. M. stniiuienil'r:im-us. 



f.t. M. seinitendinosus. 



t.A. Tendo Achillis. 



I. A'. Thickening of tendo Achillis. 



M. tibialis posticus. 



!.. M. rantus externus. 

 r..'. M. v;itus intemus. 



