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 looseh^ 

 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 w^ithers 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 



