374 LEWIS J. POLLOCK 



Head and Sherren (6) state that "Sometimes it is necessary 

 to divide an injured nerve, after sensibility to prick has already 

 begun to return to the hand, that more perfect union may be 

 obtained. Wherever such an operation has been performed, 

 the parts that had begun to recover sensibility became again 

 insensitive to prick, a proof that the recovery must have been 

 due to union, however imperfect, of the divided nerves." In 

 such cases as show return of sensibility to pain as the result of 

 actual regeneration, subsequent resection would be expected to 

 produce analgesia. Similarly, the existence of sensibility to 

 pin prick in a partially severed nerve would be destroyed if that 

 nerve be resected. The whole area of the anatomic sensory 

 supply of a nerve must be rendered analgesic following resection 

 before it can be stated that no part of the return of sensation 

 was due to overlap. In all of my cases, dissociated return of 

 pain sense occurred within the area of nerve overlap and remained 

 intact following resection and suture. Nowhere have I found 

 an illustration of dissociated return of pain sense except in such 

 an area of overlap. 



DISCUSSION 



1. The preceding observations show that the dissociated 

 return of sensibility of cutaneous pain occurs only in areas of 

 possible overlap. 



2. When several nerves serving adjacent areas are severed 

 simultaneously, sensibility to cutaneous pain is not present after 



Fig. 9 Sensory changes before and after resection and suture of various 

 peripheral nerves. A, before, A', after resection and suture of the ulnar nerve. 

 B, D, E, before, B', D', E', after resection and suture of the ulnar and median 

 nerves in cases with additional lesions of the internal cutaneous. G, before, G', 

 after resection and suture of the ulnar and median nerves. H, before, H', after 

 resection and suture of the ulnar, median, and musculo-cutaneous nerves. 

 F, before, F' after resection and suture of the median. 



A. Examined July 21, 1919; operated June 8, 1919; A' July 21, 1919. 



B. Examined April 5, 1919; operated April 4, 1919; B' May 29, 1919. 



D. Examined May 17, 1919; operated May 29, 1919; D' July 8, 1919. 



E. Examined April 1, 1919; operated April 5, 1919; E' May 29, 1919. 



F. Examined May 5, 1919; operated May 21, 1919; F' June 1, 1919. 



G. Examined April 18, 1919; operated April 18, 1919; G' May 30, 1919. 

 H. Examined June 23, 1919; operated June 29, 1919; H' July 11, 1919. 



