30 FISTULA AND POLL-EVIL 



They increase in length from the first to the 

 crest (the fifth) and then gradually diminish 

 to the twelfth. Those immediately over the 

 crest exhibit the cartilaginous ends above men- 

 tioned. The increase in length is not symmet- 

 rical, the second being almost twice as long as 

 the first. 



They are connected to one another by the 

 interspinous ligaments which complete an im- 

 pervious partition between the two lateral 

 halves of the withers. Laterally they are cov- 

 ered with the spinalis and longissimus dorsi 

 muscles. 



The spinous processes rank high in impor- 

 tance in the study of fistula of the withers. The 

 initial pathological jDrocess of typical fistula is 

 usually seated on the second and third seg- 

 ments. The cyst which constitutes the first 

 pathological change is attached to them and 

 when opened often exposes their cartilaginous 

 summits. In traumatic fistula originating 

 from superficial wounds, these processes often 

 become the seat of a stubborn osteitis that 

 descends into the cancellated tissue, sometimes 

 as far down as the bodies of the vertebra, 

 creating very chronic if not always incurable 

 conditions. 



The student of surgical anatomy should 

 remember their length at the different points, 



