SUPERIOR FACE OF THE BODY. 125 



Finally, the femur not always having the same obliquity, it forms with the 

 ilium and the ischium two angles, HOC (ilio-femoral) and FOG (ischio-Jemorat). 

 for this reason more or less closed or open. 



It will be perceived that the femur surmounts the centre of the articulation, 

 0, by the great trochanter, T. 



Among the groups of muscles we recognize 



1st. The gluteal muscles, TH, TS, carrying the femur backward when their 

 fixed point is H, or elevating the ilium when 7*is the fixed point. 



2d. The flexors of the femur, HP, principally the psoas, RP, advancing the 

 thigh when H is their fixed point, and depressing the ilium when P becomes the 

 fixed insertion. 



3d. The ischio-tibial (femoral biceps, semi-tendinosus and membranosus), 

 FI and FF, extending the femur and flexing the tibia, have as their fixed point 

 F or S; when / or /' is the fixed point, the ischium swings downward or 

 upward. 



The remaining muscles are all similar in function to those already studied. 



We observe, therefore, that there are in this region two principal groups 

 of muscles. The first, PH, flex the femur, carrying it forward ; the second, Tff, 

 FI, FVj more voluminous, extend this region. When the femoral insertion is 

 fixed these muscles are capable of producing the same movements of the croup. 

 The flexors, HP, swing the coxae downward and forward ; the extensors rotate 

 them backward. They can thus contribute directly or indirectly in supporting 

 the dorso-lumbar region. 



The croup must be studied with regard to its length, width, thiekness, 

 direction, muscular development, and particular forms. 



Length. The length is measured from the external angle of the 

 ilium (haunch) to the ischiatic tuberosity (buttock). Bourgelat con- 

 sidered it equal to the distance comprised between the summit of the 

 head and the commissures of the lips. These dimensions appear to 

 correspond in most horses of a regular conformation, except in thor- 

 oughbreds, in which the croup is relatively longer on account of the 

 exceptional smallness of the head. 



The length of the coxae is, without dispute, the most important con- 

 dition of the beauty of the croup in animals adapted to any rapid ser- 

 vice. Whilst it is not a necessity in draught-horses, it nevertheless 

 adds to their usefulness and beauty. Among Arabians this quality is 

 much appreciated. "As to the horse whose croup is as long as his 

 back and loins united, you can safely choose him even with your eyes 

 closed ; such a horse is a blessing I" This 'is one of their maxims. The 

 principal idea which this metaphor teaches is that the long croup should 

 always be preferred, to the exclusion of all others. 



The reason for this preference is readily perceived. The great 

 development of its antero-posterior diameter corresponds relatively 

 with the length of the muscles of the croup, notably those of the 



