ANTERIOR MEMBER. 



231 



The knee is called calf's knee when it is defective in its width, its 

 thickness, and in the eifacement of all the bony prominences ; it denotes 

 a general feebleness of the member, the volume of an articulation 

 being correlative also to that of the regions which confine it. 



Height. The height of the knee above the ground depends on 

 the relative length of the forearm and the canon. We have seen that 

 a long forearm gives a great advantage in the function of kmg anti- 

 brachial muscles, and it is for this reason that preference should be 

 given to a knee well descended and situated very low. In this con- 

 nection, all other things being equal, saddle- and carriage-horses have 

 the knee higher than draught-horses, a fact which can be easily ascer- 

 tained by actual measurement. Their canons are longer, their body is 

 less close to the ground. Nevertheless, tnis does not change the prin- 

 ciple which has just been laid down. The latter applies only to those 

 subjects whose conformation is comparable, and to no others. 



Direction. The vertical direction of the forearm and of the 

 canon is without doubt one of the principal conditions of the strength 

 and endurance of the anterior members. So true is this 

 that everything in the carpal articulations is so ar- 

 ranged as to determine this mode of superposition of 

 the osseous segments. Such is, however, not always the 

 direction of the knee : sometimes it is deviated forward 

 or backward from the vertical line; sometimes it is 

 within or without this axis. Hence grave defects of the 

 axis of the member, to which are given particular names. 



Thus, the horse is called over in the knees, knee- 

 sprung, when this region is curved forward (Fig. 68). 



This condition is also distinguished as acquired and 

 congenital: acquired or accidental when it is the result 

 of fatigue and excessive wear and tear of the parts; 

 congenital, on the contrary, when it exists from the time 

 of the animal's birth. 



The first case is a serious condition, indicative of the FIG. 68. 

 muscular weakness of the part, of its worn-out state, or 

 of the contraction of the posterior tendons ; such a horse is utterly un- 

 steady on his feet, is positively unsafe to ride, and may fall on his 

 knees at any moment, as is shown by the indelible scars with which 

 they are usually disfigured. 



In the second case the defect is only apparent, and in no way inter- 

 feres with a firm and steady grip of the ground or with the freedom 

 of movements. 



