MYOLOGY 205 



to that which in man is occupied by the muscles of the 

 thigh, which here are reduced in length. In other words, 

 they are not superposed, as in the liuman species, but 

 juxtaposed. This is what we will verify further on. 



The thigh, as a whole, is flattened from without inwards, 

 its transverse diameter being less in extent than its antero- 

 posterior. Its external surface is slightly rounded ; that 

 is, of course, in quadrupeds with sufficiently well-developed 

 muscles. Its internal surface is known as the flat of the 

 thigh. 



Muscles of the Posterior Region 



It is not unprofitable to recall to mind what muscles 

 form the superficial layer of this region in the human being. 

 They are the biceps cruris, semi-tendinosus, and semi- 

 membranosus. We now proceed to discover their analogues 

 in quadrupeds. 



Biceps Cruris (Fig. 68, 30 ; Fig. 69, 27 ; Fig. 70, 

 36). — It is this which, according to Bourgelat, forms the 

 central and posterior portions of the long vastus muscle 

 which we have mentioned above. 



We know that the biceps of man is so named from 

 the two portions which form its upper part. In domestic 

 quadrupeds, and also in the majority of the mammals, this 

 muscle is reduced to a single portion, that which comes from 

 the pelvis. It is therefore the portion which arises from 

 the femur which does not exist. This condition is some- 

 times found as an abnormality in the human species. 



The biceps arises from the tuberosity of the ischium ; 

 hence it is directed, widening as it goes, towards the leg, 

 where it terminates by an aponeurosis which blends with 

 the fascia lata and the aponeurosis of the leg, and then pro- 

 ceeds to be attached to the anterior border or crest of the 

 tibia. By its inferior portion it hmits externally the pos- 

 terior region of the knee — the popliteal space. 



A fibrous intersection traverses the biceps in its whole 

 length, with the result that the muscle looks as if formed of 

 two portions, one of which is situated in front of the other. 



