192 HUMAN PHYSIOLOGY. 



The gray matter is probably both insensible and inexcitdble under 

 the influence of direct stimulation. 



A transverse section of one lateral half of the cord produces 



1. On the same side, paralysis of voluntary motion, a relative or 

 absolute elevation of temperature, and an increased flow of blood 

 in the paralyzed parts; hyperesthesia, for the sense of contact, 

 tickling, pain, and temperature. 



2. On the opposite side, complete anesthesia as regards contact, 

 tickling, and temperature in the parts corresponding to those 

 which are paralyzed in the opposite side, with a complete preserva- 

 tion of voluntary power and of the muscular sense. 



A vertical section through the middle of the. gray matter results 

 in the loss of sensation on both sides of the body below the section, 

 but no loss of voluntary power. 



Paralysis from Injuries of the Spinal Cord. 



Seat of Lesion. If it be in the lower part of the sacral canal, 

 there is paralysis of the compressor urethrae, accelerator urinse, and 

 sphincter ani muscles ; no paralysis of the muscles of the leg. 



At the Upper Limit of the Sacral Region. Paralysis of the muscles 

 of the bladder, rectum and anus ; loss of sensation and motion in the 

 muscles of the legs, except those supplied by the anterior crural and 

 obturator viz., psoas iliacus, sartorius, pectineus, adductor longus, 

 magnus, and brevis, obturator, vastus externus and internus, etc. 



At the Upper Limit of the Lumbar Region. Sensation and motion 

 paralyzed in both legs ; loss of power over the rectum and bladder ; 

 paralysis of the muscular walls of the abdomen, interfering with 

 expiratory movements. 



At the Lower Portion of the Cervical Region. Paralysis of the 

 legs, etc., as in the foregoing ; in addition, paralysis of all the inter- 

 costal muscles and consequent interference with respiratory move- 

 ments ; paralysis of muscles of the upper extremities, except those 

 of the shoulders. 



Above the Middle of the Cervical Region. In addition to the 

 preceding, difficulty of deglutition and vocalization, contraction of the 

 pupils, paralysis of the diaphragm, scalene muscles, intercostals, 

 and many of the accessory respiratory muscles ; death resulting im- 

 mediately from arrest of respiratory movements. 



