Chap, xtx.] THE BUTTOCK. 431 



Ziemssen's Cyclopaedia, where paralysis of the nerve 

 followed its compression by the contracting scar of a 

 bed-sore. 



Nerve stretching. The great sciatic nerve has 

 been frequently cut down upon and roughly stretched 

 for the relief of certain nervous affections of the lirnb. 

 In connection with this procedure it is important 

 to know how great an amount of traction may be 

 brought to bear upon this and other nerves without 

 the cord giving way. Trombetta, who has paid much 

 attention to this matter, gives the following weights 

 as those required to break the undermentioned nerves : 

 great sciatic, 183 pounds; internal popliteal, 114 

 pounds ; anterior crural, 83 pounds ; median, 83 

 pounds; ulnar and radial, 59 pounds; brachial 

 plexus in the neck, 48 to 63 pounds ; and brachial 

 plexus in the axilla, 35 to 81 pounds. (In each 

 instance fractions have been omitted.) It must 

 be borne in mind, however, as pointed out by Mr. 

 Symington (Lancet, 1878), that in forcibly stretching 

 the great sciatic nerve the trunk may be torn away 

 from its attachments to the soft spinal cord before a 

 sufficient force has been applied to rupture the nerve 

 at the point stretched. The same observation applies 

 to other large nerve-cords, such as those of the brachial 

 plexus, that are stretched at a spot not far from their 

 spinal connections. 



The skin of the buttock is well supplied with 

 nerves, and tactile sensibility is almost as acute in 

 this part as it is over the back of the hand, while it is 

 more acute than is like sensibility in such parts as 

 the back of the neck, the middle of the thigh, and the 

 middle of the back. The sensation of the gluteal 

 integument is derived from a number of different 

 nerves, and it may possibly interest a school-boy, who 

 has been recently birched, to know that the painful 

 sensations reached his sensorium through some or all 



