POSTERIOR MEMBER. 237 



CHAPTER II. 



POSTERIOR MEMBER. 



We have already stated the reasons for uniting the description of 

 the croup with that of the trunk, and need not return to them here. 



The regions of the posterior members correspond to those of the 

 anterior, with some unimportant variations consequent upon the par- 

 ticular mode in which these parts execute their movements. 



Thus, the thigh is the counterpart of the arm ; the stijie, of the 

 elbow ; the leg, of the forearm ; the hock, of the knee. Such are the 

 diverse regions which it remains for us to examine. 



. A.— The Thigh and the Buttock. 



Situation ; Limits ; Anatomical Base. — We deem it advis- 

 able to combine the thigh and the buttock in one description, since there 

 is so close a relation between them. 



We will merely consider the latter as that part of the former which 

 is charged with the flexion of the tibia, the extension of the femur, and 

 the rotation of the coxa. 



The thigh is the region where the posterior member becomes sepa- 

 rated from the trunk. It is limited above by the croiip and the 

 haunch; below, by the leg and the stifle; in front, by the flank; 

 inwardly, by the groin (in both sexes), the sheath and the scrotum in 

 the male and the mammary glands in the female ; behind, finally, it is 

 altogether free, and is simply in relation with the trunk and the hairs 

 of the tail. 



Its anatomical base consists of the femur and of numerous muscles 

 ^vhich, originating in adjoining regions, terminate here, or, on the con- 

 trary, are detached here to terminate on the sections immediately below 

 it, — viz., the leg and the foot. 



Form. — The thigh offers for study two surfaces and two borders. 



The external surface is slightly rounded, according to its length and its 

 width, in a horse in good condition. It forms, in such cases, below the croup, an 

 almost vertical plane, which blends off below with the corresponding surface of 

 the leg, and, in front, with the side of the flank. But hard work and insufficient 

 food render the muscular interstices and the natural prominences of the skeleton 

 very apparent : the femur is indicated by a thick longitudinal elevation, in front 

 of which the muscles appear hollow, in consequence of the contraction of the 

 flank ; the ischiatic tuberosity and the trochanter become very salient, and leave 

 between them a deep furrow which separates the superficial gluteus muscle 



