36 PRINCIPLES Of veterinary sUrGery 



is divided anatomically into the coronary cushion, which 

 forms the wall, the sensitive laminae, which forms the insen- 

 sitive laminae, and the velvety tissue, which forms the sole 

 and the frog. The coronary cushion which occupies the su- 

 perior border of the hoof is studded with papillae, each one oi 

 which produces an individual wall-fibre. If all of the wall is 

 removed these papillae will reproduce it in its entirety in 

 about eight months. At the heels the distance between cor- 

 onet and sole being short the reproduction is complete in 

 eight weeks to three months. When the coronary cushion is 

 divided transversely from disease or injury and the wound 

 heals by second intention the scar tissue which connects the 

 separated ends will contain a dearth of genetic cells and the 

 wall fibers proceeding from them will be so defective in qual- 

 ity and often in quantity as to produce a seam in the wall of 

 the hoof that will vary in character according to the amount 

 of scar tissue that was required to heal the breach. This 

 scarcity of hoof-producing cells in the scar may however not 

 be permanent, as the regenerating process in the scar tissue 

 may continue month after month, and even for several years 

 with the result of again bringing the wall back to its normal 

 condition. Such seams of abnormal hoof in young horses 

 may entirely disappear after several years through the grad- 

 ual resumption of the normal function of the coronary cush- 

 ion. More often, however, after severe injuries, an indelible 

 blemish remains. 



When the sensitive laminae are destroyed over a consid- 

 able area, their function of uniting the wall to the bone is 

 never entirely restored although the defect may not be no- 

 ticeable from without. No matter how trivial is the loss of 

 tissue in this structure, the accordion-pleat arrangement is 

 never restored. An irregular arrangement of the pleating 

 always results and often the surface remains quite smooth 

 and a considerable space intervenes between it and the 



