82 SPINAL ANAESTHESIA 



Spinal Anaesthesia. Intraspinal injections of sterilised 

 solution of cocaine, stovaine, tropacocaine, novocaine, or 

 other suitable anaesthetic, may be used to produce anaes- 

 thesia of the posterior portions of the body, prior to opera- 

 tions on the hind limbs and pelvic organs. This method, 

 introduced in human surgery by Dr. Boer, was first tried 

 on veterinary patients by Guille and Sendrail. Under the 

 influence of lumbar anaesthesia, neurectomy, tenotomy, and 

 cauterisation of the hind limbs, oophrectomy, the reduction 

 of inverted uterus, castration, urethrotomy, and some 

 hernial operations can be painlessly performed, and without 

 the risks attending general anaesthesia. Injection is made 

 through the lumbosacral space at the point of intersection 

 of two lines, one median uniting the last lumbar and first 

 sacral vertebrae, the other transverse, connecting the summits 

 of the internal angles of the haunch. The skin of the region 

 is shaved and carefully disinfected, and a sterilised hollow 

 needle or fine trocar and cannula is implanted perpendicu- 

 larly, to a depth of one half to three inches (dog or cat), 

 or four to six inches (horse), at the point of intersection of 

 the two lines in the dog and cat, and about three-fourths 

 of an inch in front of this point in the horse. The entrance 

 of the needle into the subdural space is indicated by the 

 escape of cerebro-spinal fluid. Recently attempts have 

 been made in the dog to enlarge the area of anaesthesia by 

 injecting the drug through the occipito-atloid ligament, but 

 at this situation the operation is more dangerous to the 

 patient than lumbar injection. In practising injection 

 at the poll, the dog's head should be held well elevated, 

 and care must be taken to prevent puncture of the cord. 

 Doses. Solution of cocaine (2 per cent.), dog and cat, 

 fl\v to Tl\15 ; horses, H\xx to TT\xlv ; solution of stovaine 

 (5 per cent.), dog, H\20 to Tl\30 ; cat, H\10 to 1T[20 ; horse, 

 3j to 3ijss. 



ACTION OF DRUGS ON THE SPINAL CORD 

 AND MEDULLA 



SPINAL STIMULANTS SPINAL DEPRESSANTS 



As on the brain, so on the spinal cord and medulla drugs 

 act in one of two ways, namely, to stimulate or to depress. 



