THE ANTERIOR EXTREMITIES. 81 



are seven principal carpal bones; in the recent subject, when 

 the horse is carefully dissected, there is always found an 

 osselet of the shape and size of a pea, situated behind 

 the trapezoid, with which it is articulated. With this, 

 the knee consists of eight bones : the upper articulates 

 with the inferior extremity of the radius ; and the low-er with 

 the superior of the cannon and the two small splent bones. 

 Six of the eight bones are to be seen from the front ; ranged 

 in two row^s ; of which the top one is the thicker ; each row 

 being composed of three bones. Tlie three upon three, how- 

 ever, do not join both in the same place ; but have articula- 

 tions similar to bricks in a wall ; that is, the two uppermost 

 are joined upon the middle of a solid bone beneath. Each 

 of these row'S have free articular surfaces, both above and 

 below ; as though they composed but one bone, being smooth 

 and plentifully lubricated by synovia. Their motion, also, 

 is greater in one direction ; the rows being capable of such 

 separation as allows the heel to touch the fore arm. Turn- 

 ing to the hind part of the knee, we can see two additional 

 bones. The very small pea-like one, situated against the 

 lower row ; and a large rounded square bone {Skel. n), arti- 

 culating with both rows ; and projecting out a considerable 

 distance from the other bones of the knee. The reason of 

 this projection is to afford leverage for the hold of tendons 

 through which muscles exert their power ; and likewise to 

 afford a shield or protection to the back sinews or flexor 

 tendons, which pass between this bone and the others of 

 the knee. 



The reason for forming the knee of so many distinct 

 bones is very apparent. Concussion is lessened by a divi- 

 sion of parts ; a fact well known to man, who hangs out 

 sand and cotton-bags to break the force of cannon balls, or 

 take off the concussion of the blow. This result is mate- 

 rially aided by the synovia, or fluid between the different 

 rows ; and hence we find the effects of concussion below 

 rather than above the knee. The bones, moreover, though 

 bound closely together by means of ligaments, and each 

 individually fixed, nevertheless, as a whole, admit of con- 

 siderable lateral motion. Thus a powerful wrench, to which 

 the foot in progression is exposed, may take place without 

 dislocation. 



