Anatomical Changes. Synii 



751 



places, especially arouinl the vessels, the walls of which are much thickened, it is infil- 

 trated with cells. In most of the nerve fibers the medullary sheath is degenerated 

 and in many bundles no fibers can be 

 made out. The cells of the spinal 

 ganglia show various stages of chroma- 

 tolysis and destruction of the nuclei. 

 The spinal cord appears normal and in 

 a single case only could ascending de- 

 generation of the posterior column lie 

 made out with certainty where the pro- 

 cess involved the intradural portion of 

 the nerve roots and the last two lum- 

 bar nerves were also diseased. 



The muscles of the tail appear 

 for the most part degenerated and in 

 more advanced cases somewhat similar 

 lesions have been found in the mus- 

 cles of the croup. Of the peripheral 

 nerves the following are usually in a 

 condition of degeneration; the nerves 

 of the tail, the pudic nerves, the sn- 

 perior^ and inferior gluteal nerves, the 

 posterior cutaneous branches of the 

 dorsal branches of the sacral plexus 

 and the posterior hemorrhoidal nerve. 



Symptoms. In the early 

 stages tlie sensory nerves are 

 stimnlatecl by the connective 

 tissue which gradually increases 

 in amount and contracts around 

 them, with the result that the 

 skin of the tail and the peri- 

 neum are hyperesthetic. In 

 consequence of this the animal 

 rubs these parts against any 

 rigid object and, finally, there 

 are symptoms of great restless- 

 ness. In a case recorded by 

 Dexler the onset of the disease 

 was marked by severe and per- 

 sistent priapism. The attend- 

 ants do not as a rule notice this 

 and the rubbing of the tail is 

 put down to other causes. The 

 matted condition of the hair on 

 the root of the tail indicates 

 that the animal has suffered 

 from severe irritation. In one 

 case (Hutyra and Marek) spas- 

 modic contractions of the 

 gluteal muscles were observed 

 if a loud noise were made or a 

 person approached the animal. 

 The other symptoms are 

 far more noticeable. The most 

 prominent is paralysis of the 



Fig. 110. Terminal portion of the spinal 

 cord with the cauda equina from a case 

 of paralysis of the tail and sphincters. 

 L;)-LG last two lumbar nerves. S1-S5 

 sacral nerves, of wliich numbers 4 and 

 5 are enclosed, together with the first 

 two coccigeal nerves. C1-C2 and the 

 filum terniinale, in an elongated, thick- 

 ening which is much larger on the right 

 side. Between S5 and C2 there was 

 marked congestion and some hemor- 

 rhages were also present. The speci- 

 men was obtained from the horse shown 

 in fig. 112. 



