20 FISTULA AND POLL-EVIL 
formation of the crest of the neck (ewe-neck) 
results. It may be said to reinforce the “roof 
of the withers” anteriorly. 
Other Structures Important Surgically 
The splenius and the serratus cervicis are 
related to, in fact occupy, the anterior part of 
the withers. They lie immediately below the 
rhomboideus cervicalis and beneath the trap- 
ezius cervicalis. Their upper margins are re- 
lated to the former. Just in front of the car- 
tilage of prolongation they are very loosely 
attached to the rhomboideus and thus afford 
the portal for surgical invasion above referred 
to. They are thick, tuberous curtain-like mus- 
cles forming the bulk of the crest of the neck 
and on account of their thickness prevent 
facile direct invasion to the bottom of pus ca- 
vities which are usually located below this mar- 
gin at the level of the second dorsal spine. 
These two thick muscles, in short, form the 
lower part of the lateral walls of the pus cav- 
ity in fistula of the withers. The treatment of 
fistula of the withers would be a lesser problem 
if the pus cavity could be drained over the dor- 
sal margin of these muscles instead of through 
them. 
The longissimus dorsi. The longissimus dorsi 
at the withers occupies the space between the 
