64 THE MUSCULAK SYgTEM OF THE FEOG 



a. The rectus antic^s femoris forms the middle 

 division of the tiipeps : it arises from the ven- 

 tral border of the posterior third of the ilimn, 

 in f ron/ of the acetabulum : about , half -way 

 down ihe thigh it joins the next ^vision. 



0. The vastly internum, the^Jpj-eaxia/ division of 

 the xrice|is, is a large musple"^ arising from 

 the/ ventraly'and aB!terior/border of the 

 acejcabulum,/aihi lying in tlie thigh between 

 thtt sartoriiis anoNthe reclms anticus. 



y. The /vastus, extemus, the. /ostaxial division of 

 tie triceps, arises' fromHhe posterior edge 

 of the dorsal crest of th6 ilium, and joins 

 the other two divisioiis of the triceps about 

 the junction of the middle and distal thirds 

 of the thigh. 



c. Superficial mi^cles of the postaxial (apparent dorsal) 

 surface of the' thigh. 



i. The glutseus has been already noticed : it lies in 

 the thigh between the rectus anticus and the 

 vastus extemus. 

 —X-- ii. The biceps is a long slender muscle which arises 

 from the crest of the ffliu^) just above, the 

 acetabulmn : it lies in theffiigh along the inner 

 border of the vastus extemus, and is inserted by 

 a flattened tfitiHinffiisPiYpaTi sion into the d istal 

 end of th^^^nurlind the iieacl of the tibi^ 



The semimemSian6gUS iSAfetout nni!56l« lyiil^ along 

 the inner side of the biceps, between it and the 

 rectus intemusjja^^; — ib.a;£ises from the dorsal 

 angle of the ^^jaT^m pI^iS^ ust beneath the 

 cloacal openiog^ajidis inserted into the back of 

 the head of thd QilS^ It is divided about its 

 • middle by an oblique tendinous intersection. 



The pyriformis is a slender muscle which arises from 

 the tip of the urostyle, passes backwards and 

 outwards between the 'bicepF^Bd-~^ii£^_sem- 

 mranbranosus, and is inserted into the feimraf 

 the junction of Hfts proximal and middle thii-ds. 



— ( — iii, 



