704 



Compression of the Spinal Cord. 



of the change is iiiflicated by the histolog-y of the lesion. Tliat the condition is 

 inflammatory is also indicated by the facts that in some cases there is a sinud- 

 taneous ulcerative inflammation of some of the joints of the limbs (Hutyra & 

 Marek), and that Cadcae has observed exostosis-formation in the joints of the 

 limbs in many cases. 



Intervertebral Ossification (Enostosis intervertebralis). In 

 old horses and dogs there sometimes develop, as a result of an 

 osteoplastic periostitis in the neighborhood of the intervertebral 

 discs, growths composed of true bone. These growths var}- in 

 size and project into tlie vertebral canal and join the opposed 

 parts of two or more joints by means of closely set toothlike 

 projections, so firmly that the whole spine with the exception of 

 the neck is converted into a solid cohnnn. The process occurs 

 in nine-tenths of the cases in the most mobile parts of the dorso- 

 lumbar sections of the spine, that is, the parts which are espe- 



^ 



Fig. 



^^S!!Sg 



100. Vertebral tuljei 

 vertebra, (b) 



j.iii. ,a, 1 ulii-rculous growth in a dorsal 

 liowing "hour glass" compression. 



cially exposed to strains. Similar growths may also result 

 from fracture of vertebra^ (Cadeac, Dexler, Ryder, Hutyra & 

 Marek. 



Ossifying Pachymeningitis (see page 680). This condition 

 in some cases leads to compression of the cord. 



Tuberculosis. Both in cattle and in the pig tuberculosis is 

 frequently responsible for compression of the spinal cord. A 

 similar case has been recorded l)y Megnin in the horse. Tuber- 

 culosis of the bones occurs most frequently in the dorsal por- 

 tion of the spine, and more rarely in the cervical and lumbar 

 regions. Of eleven cases collected by Hamoir, seven involved 

 the back, two the neck and two the lumbar bones. The disease 

 leads to the production of softened or caseous centers, or in 

 some cases to the formation of sarcomalike masses with consid- 

 erable enlargement of the verteliral bodies, or more rarely the 



