PATELLAR DESMOTOMY 



227 



an oblique direction, toward the supero-internal part of the 

 tibia. The middle straight ligament is found extending ver- 

 tically from the middle of the patella to the tibial crest. It 

 stands out prominently, much more so than the internal. By 

 palpating inwardly from the middle straight a V-shaped de- 

 pression dividing it from the internal straight easily deter- 

 mines the anterior edge of the latter, which exists in the 

 forrh of a firm flat body about one inch in width in the ma- 

 ture normal horse, proportionately smaller in the colt, and 

 more or less rounded in a patient affected with habitual luxa- 

 tion. The direction of the ligament varies somewhat with 

 the position of the stifle. Flexion increases its obliquity; ex- 

 tension straightens it. It is essential in this step to determine 



Fig. 120 — Patellar Desmotomy. 



its outlines by cautious palpation, so that the line of incision 

 can be made directly along its long axis and as near as pos- 

 sible to the middle of its breadth. 



Second Step.— Making the Cutaneous Incision.— Having 

 determined the exact location of the ligament, an incision is 

 made through the skin from the superior part of its middle 

 third downward to and slightly beyond its insertion to the 

 tibia, in all about two and a half inches long. Although the 

 region is not very vascular, the cutaneous incision gives a 

 little haemorrhage that must first be controlled perfectly be- 

 fore proceeding, in order that the subsequent dissection is 

 not hindered by masking blood. 



Third Step.— Searching for the Lateral Edges of the Lig- 



