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 coy- 
ered with the spinalis and longissimus dorsi 
muscles. 
The spmous processes rank high in impor- 
tance in the study of fistula of the withers. The 
initial pathological process of typical fistule 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 fistule 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, 
