QUESTIONS AND ANSWERS 49 



are large, flattened and incline forward and downward ; there is no 

 spinous process, but a roughened surface instead. At the base of 

 each transverse process are two foramina which traverse it from 

 below upward. 



The second or axis is the longest of all the cervical vertebras. 

 It terminates anteriorly in a conical process, the odontoid, which 

 is convex, smooth below and concave above to articulate yrith the 

 atlas. The spinous process is very prominent and elongated antero- 

 posteriorly. The transverse processes are only slightly developed. 

 Describe the common characteristics of vertebrae. 



Each vertebra has a body, and an arch enclosing the spinal canal. 

 The superior face of the body forms the lower boundary of the 

 spinal canal. The anterior extremity of the body is convex and the 

 posterior is concave. The arch projects upward from the body and 

 is composed of pedicles, laminse, transverse, spinous and articular 

 processes. The articular processes, four in number, are distributed 

 two anteriorly and two posteriorly. The anterior pair look upward, 

 the posterior look downward. 

 What are true vertebrae? Give the number in the horse, ox and dog. 



True vertebrae are those constituting the cervical, dorsal and lum- 

 , bar regions of the spinal column. There are 30 in the horse, 26 in 

 the ox, and 27 in the dog. 

 Describe the sternum of the horse and compare it with the sternum of 

 the ox and dog. 



The sternum is the osteocartilaginous body which forms the in- 

 ferior boundary of the thoracic cavity. It shows on either side 

 articulations for the first eight ribs; anteriorly, it shows a carti- 

 laginous mass, flattened on each side and curved upward, the cervical 

 prolongation or presternum; posteriorly it is flattened above and 

 below to form the xiphoid or ensiform cartilage. It is flattened, 

 laterally, in its anterior two-thirds, and from above downward in its 

 posterior one-third. 



The sternum never undergoes complete ossification. It is de- 

 veloped, in the horse, from six single nuclei which never coalesce 

 to form a single piece. 



In the ox, the sternum is made up of seven parts; they are 

 much more compact than those in the horse, and are united to each 

 other, with the exception of the first. There is no cervical pro- 

 longation and the xiphoid cartilage is feebly developed. 



In the sternum of the dog, eight component parts are noted. 

 They are hollowed in their middle part and thick at their ends. 

 They are never ossified to each other. 

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