22 FISTULA AND POLL-EVIL 



vicis, posteriorly by the serratus thoracis and 

 the scapular cartilage. Its floor is formed by 

 the longissimiis dorsi and its roof by the trap- 

 ezius and rhomboideus. The central partition 

 is constituted of the dorsal spines, spinalis dorsi 

 posteriorly and the lamellar portion of the 

 ligamentum nuchse covered with the com- 

 plexus anteriorly. The bottom of the trough 

 which must be reached for effectual drainage 

 can be penetrated only with difficulty and the 

 risk of inviting complications in structures not 

 previously implicated. Furthermore, these 

 muscles being in constant use in locomotion, 

 respiratory acts and movements of the neck, 

 tend to encourage the burrowing of pus into 

 still more inaccessible recesses. 



Thus we find the musculature of primal im- 

 portance in any study of fistula of the withers. 

 It bounds initial abscess cavities in places 

 difficult of access for drainage, they move upon 

 each other and favor the distribution of puru- 

 lent products into new fields, where secondary 

 abscesses are formed, and it exhibits a remark- 

 able trend toward fibrosis under the influence 

 of the chronic inflammation of adjacent parts. 



The Ligaments 



The ligaments implicated in fistula of the 

 withers are the ligamentum nuch^e and the 



