782 PARALYSIS OF BRACHIAL PLEXUS. 



resumed. Moller suspected thrombosis, but although the post- 

 mortem was conducted with the greatest care, nothing could be 

 detected, so the cause of this rare disturbance remained unexplained. 

 There was no muscular atrophy. 



VIII.— PARALYSIS OF THE BRACHIAL PLEXUS. 



Paralysis of the brachial plexus usually arises from some local 

 cause. Compression of the plexus between the shoulder and the 

 trunk may happen in operations where the horse is kept lying for 

 a long time in one position as with a fore-foot fixed to a hind-limb. 

 Holmann saw paralysis of the entire muscles of the fore-limb in a 

 horse following on a fall and found on post-mortem severe bleeding 

 around the brachial plexus. From his description it is, however, 

 clear that simultaneous rupture of the serratus magnus existed, 

 for the horse was not only unable to move the foot, but the body 

 sank several inches at each attempt to place weight on the limb. 

 The limb was also abnormally abducted. 



Trasbot describes a case of paralysis of the brachial plexus in 

 which hemiplegia appeared later. Recovery occurred in fifteen 

 days. This case is also not quite clear. Wilson saw hemiplegia 

 in a horse after rolling over backwards, and Anacker has seen it in 

 a sucking-pig. 



In dogs it is commoner, and occurs both as peripheral paralysis 

 and as hemiplegia. In the latter condition Moller repeatedly saw 

 well-marked spastic lameness in all the muscles of the shoulder, 

 most notably in the triceps group ; this was followed by long- 

 continued disturbance in movement. 



Paralysis of the brachial plexus in horses is sometimes of central 

 origin ; in these cases other troubles precede, accompany, or follow 

 it. A seven-year-old mare showed in December, 1887, right-sided 

 facial paralysis ; in January, 1888, left-sided hemiplegia. The toe 

 of the left fore-foot was dragged along the ground. Soon afterwards 

 a small cataract appeared in the right eye, and gradually involved 

 the entire lens. The post-mortem showed a tumour as large as a 

 walnut between the petrous portion of the right temporal bone and 

 the cerebellum ; it extended to the pons varolii and restiform bodies 

 of the medulla. Its interior was occupied by a small quantity of 

 pus. 



Shocks from the high-pressure currents used to operate street 

 trams or railways may produce brachial paralysis, which, however, 

 passes away, provided the shock has only been momentary. 



