108 FISTULA AND POLL-EVIL 



as a pillar for the ligamentum nuchas to bridge 

 over the space between it and the nuchal (oc- 

 cipital) crest. The ligamentum nuchse is, how- 

 ever, attached to it only by the lamellar por- 

 tion, which at this point is very thick. 



Tlie nuchal {occipital) crest is a process of 

 the occipital bone extending upward to give 

 attachment to the ligamentum nuchee 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-acvoid 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- 



