MYOLOGY 209 



spite of the fact that none of the gluteal muscles take any 

 part in the structure of this region. But the appearances, 

 to a certain extent, justify the preservation of this name. 

 Indeed, because of the groove which separates the gluteal 

 region of one side from that of the opposite side, and 

 from the position of the anal orifice in the superior part of 

 this groove, we may admit the name which, in hippology, 

 has been given to this part of the thigh. 



In addition to the reasons just given, and which are 

 justified especially by the position occupied by the muscular 

 mass formed by the union of the two muscles, there is 

 another which, this time, has a relation to a certain 

 detail of form. In the superior part of the convexit}^, 

 which the gluteal region describes in the greater part of its 

 extent, there is found a more salient point, greatly accentu- 

 ated in lean animals, due to the presence of the tuberosity 

 of the ischium ; it is the point or angle of the buttock. At 

 this level, and near the median line, the semi-membranosus, 

 not aponeurotic, but fleshy, and even thicker there than 

 anywhere else, sometimes produces a sharply localized 

 prominence. And as this prominence is situated on the 

 outer side of the anal orifice, the resemblance to a small 

 ' buttock ' is still more marked. 



In lean horses a deep groove separates the mass formed 

 by the semi-membranosus and semi-tendinosus from that 

 of the other muscles of the thigh situated more in front ; 

 this groove is known by a name which in this case is 

 remarkably expressive — that of the ' line of poverty.' 



If we examine the gluteal region as a whole by looking 

 at the thigh from the side, we plainly see the graceful 

 curve produced by the general convexity above indicated. 

 We return to this point, in order to add that, in its lower 

 part, this curve alters its character ; that is to say, it 

 is replaced by a slight concavity. This, which is designated 

 under the name of the fold of the buttock, is situated close to 

 the level of articulation of the leg with the thigh-bone. 



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