OF THE SPINAL CORD 205 



of both legs. In the early stages the diagnosis from 

 syringomyelia may be only a matter of opinion. 



4. In some cases it may produce bilateral spastic 

 paralysis with involvement of the sphincter func- 

 tions and with anaesthesia without any dissociation 

 phenomena. The diagnosis is then very difficult. 



Each of the thirty-one nerve-roots issuing from 

 the spinal cord has a definite distribution, which may 

 be motor, sensory, and visceral, and these have now 

 been ascertained with some accuracy by a combina- 

 tion of anatomical, physiological, and clinical 

 methods. As given in the various textbooks and 

 monographs, the information is a good deal more 

 than most of us can carry conveniently in our 

 memories. It is hoped that the bare elements set 

 down in the table may be found easier to remember, 

 and adequate for most purposes. No two accounts 

 agree exactly. 



The main points may be emphasized first. With 

 regard to the sensory distribution, there is a good 

 deal of overlap, especially in the hand, where the 

 seventh cervical supplies the radial half, the eighth 

 cervical the inner half, and the first dorsal the one 

 and a half fingers to which the ulnar nerve may be 

 traced. The twelve dorsal nerves supply the chest 

 and abdomen in bands like successive strips of 

 plaster stretched round the body ; the nipple lies 

 between the fourth and fifth dorsal, and the umbilicus 

 between the ninth and tenth. If we place the open 

 hand on the thigh just below and parallel to Poupart's 

 ligament, we cover the first lumbar area ; the next 

 handbreadth below is the second lumbar, and the 



