84 THE ARTISTIC ANATOMY OF ANIMALS 



thus necessarily placed in a direction forwards and outwards, 

 and the knee is further removed from the axis of the trunk 

 than is the articulation which unites the thigh with the 

 pelvis. 



The femur, like the humerus, is almost completely en- 

 veloped by muscular masses, which bind it to the lateral 

 walls of the abdomen. Its inferior extremity alone is free, 

 and is always the more so in proportion to its elongation — 

 that is to say, as it belongs to an animal whose foot is more 

 divided. The femur in this respect conforms to the law 

 which we have indicated in cormection with the bone of the 

 arm, in which the development, as to length, is in propor- 

 tion to the division of the hand. 



If we compare the femur of certain animals with that 

 of man, we see that the corresponding details of form 

 are readily recognisable, but they are slightly modified. 

 Thus, on examining the superior extremity, we find there 

 a head, a neck, a great trochanter, and a lesser ; but the 

 neck is usually short and thick, and the great trochanter 

 does not occupy the same level with regard to the articular 

 head of the bone. In man, the great trochanter does not 

 rise to the level of the head of the femur ; in the dog and 

 the cat it approaches that level ; in the horse and in 

 ruminants it rises above it. 



With regard to the inferior extremity, its surfaces 

 undergo modifications which are further accentuated as 

 we pass from the digitigrades to the ungulates, or un- 

 guligrades. We know that in man the femoral trochlea 

 is continuous behind, without interruption, with the con- 

 dyles — that is to say, that each of the condyles is the con- 

 tinuation of one of the lips of the trochlea. We have just 

 said that the trochlea is continuous without interruption 

 with the condyles ; this is accurate. Nevertheless, we 

 must remark that, at the level of the junction of these 

 surfaces, the bone presents a slight constriction, which is 

 more marked on the external than on the internal aspect. 

 This constriction, which is but slightly marked in man, is 

 accentuated in the dog and the cat ; in the ruminants and 

 the solipeds it is still more pronounced so that we may 



