108 FISTULA AND POLL-EVIL 
as a pillar for the ligamentum nuche to bridge 
over the space between it and the nuchal (oc- 
cipital) crest. The ligamentum nuchez is, how- 
ever, attached to it only by the lamellar por- 
tion, which at this point is very thick. 
The nuchal (occipital) crest is a process of 
the occipital bone extending upward to give 
attachment to the ligamentum nuche and to 
the muscles of the poll. It has a rough border 
and a somewhat concave posterior face which 
is depressed at one point on each side of the 
median line to receive each half of the ligament. 
Its upper outlines determine the profile of the 
space between the ears. 
The compact tissue of the occipital crest is 
dense and hard particularly along the summit. 
The cells of the cancellated tissue are large and 
the plates separating them are thin and there- | 
fore easily permeated with inflammatory proc- 
esses. Although the occipital crest is not en- 
croached upon by disease in poll-evil itself, it 
sometimes becomes affected by a chronic os- 
teitis from chiseling into it to effect drainage 
as recommended by Williams. 
The atlanto-axoid ligament covers the gap 
intervening dorsally between the anterior por- 
tions of the axis and the posterior part of the 
atlas. This space is about an inch and a half 
to two inches long and about an inch wide, be- 
