18 FISTULA AND POLL-EVIL 
is bisected vertically with a central aponeurosis 
that is attached ventrally to the tuber spine of 
the scapula. The anterior part is the trapezius 
cervicalis and the posterior the trapezius thora- 
calis. 
The Roof of the Withers 
Together with the skin, the fascia and the 
panniculus carnosis, the trapezius muscles may 
be regarded as the “roof of the withers.” 
It is under this roof that typical fistule of 
the withers develop and beneath which the 
atypical (traumatic) fistulae burrow in direc- 
tions of resistance less than that afforded by 
its dense, aponeurotic character. 
Rhomboideus Thoracalis 
The rhomboideus thoracalis extends from 
the spinous processes of the second, third, 
fourth, fifth, sixth and seventh dorsal verte- 
bre in a downward and outward direction to 
the mesial face of the scapular cartilage. It 
constitutes a thick, heavy curtain forming a 
“second or inner roof of the withers.” Com- 
pared with the structures of a building, it 
might be said to be a curtain, sagging slightly 
in the middle, that extends from the comb of 
the roof to a point on the wall just beneath the 
plate beam. It is very loosely attached to the 
