158 
HOWARD AYERS 
ABBREVIATIONS 
A-B line indicates the position of the 
aorta with reference to the myotomes 
C, sp:nal cord 
D, dorsal spinal nerve 
L, subdural lymph space 
M, body of the myotome adjacent to 
the ventral root 
M’, muscle fibers inserting close upon 
the motor root 
M’’, muscle fibers inserting on the dura 
and among the fibers of the ventral 
root 
V, ventral spinal nerve 
d, ramus dorsalis of dorsal spinal nerve 
1, first branch of motor root, runs to 
preceding myotome 
2, second branch of motor root, runs to 
dorsal horn of myotome 
3, third branch of motor root, runs to 
ventral horn of myotome 
4, fourth branch of motor root, runs to 
succeeding myotome 
5, fifth branch of motor root, runs to 
aortic plexus 
