OSTEOLOGY AND ARTHROLOGY 



dorsal vertebrae are the most developed and are directed 

 obliquely upwards and backwards. As we approach the 

 last vertebrae of this region, the processes become shorter 

 and tend to become vertical, and the last ones are even, in 

 some cases, directed upwards and forwards ; this disposition 

 is well marked in the dog and the cat. In the cetaceans, on 

 the contrary, the length of the spinous processes increases 

 from the first to the last. 



In the horse the spinous processes of the first dorsal 



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Fig. 4. — Lumbar Vertebr.e of a Quadruped (the Horse) : Superior 



Surface. 



I, Spinous process ; 2, anterior articular process and transverse process 

 of the first lumbar vertebra of the left side ; 3, costiforni process. 



vertebrae produce the prominence at the anterior limit of the 

 trunk, where the mane ends, which is known as the withers. 



The lumbar vertebrae are thicker than the preceding ; 

 they are known by their short and latterly-flattened spinous 

 processes, and still more readily by their transverse processes, 

 which, as they are evidently atrophied ribs, it is more 

 accurate to denominate costiform processes (Fig, 4). These 

 are long, flattened from above downwards, and directed 

 outwards and forwards. 



The true transverse processes are represented by tubercles 



