CHARACTERS OF THE CERVICAL VERTEBRA. 117 



bral cartilages ; while the transverse and spinous processes serve as levers for 

 the attachment of muscles which move the different parts of the spine. Lastly, 

 between each pair of vertebrae, apertures exist through which the spinal nerves 

 pass from the cord. Each of these constituent parts must now be separately 

 examined. 



The Body is the largest and most solid part of a vertebra. Above and below, 

 it is slightly concave, presenting a rim around its circumference; and its upper 

 and lower surfaces are rough, for the attachment of the intervertebral fibro- 

 cartilages. In front, it is convex from side to side, concave from above down- 

 wards. Behind, it is flat from above downwards and slightly concave from 

 side to side. Its anterior surface is perforated by a few small apertures, for 

 the passage of nutrient vessels; whilst, on the posterior surface, is a single 

 large irregular aperture, or occasionally more than one, for the exit of veins 

 from the body of the vertebra, the vense basis vertebrae. 



The Pedicles project backwards, one on each side, from the upper part of the 

 body of the vertebra, at the line of junction of its posterior and lateral surfaces. 

 The concavities above and below the pedicles are the intervertebral notches ; they 

 are four in number, two on each side, the inferior ones being generally the 

 deeper. When the vertebra are articulated, the notches of each contiguous 

 pair of bones form the intervertebral foramina which communicate with the 

 spinal canal and transmit the spinal nerves. 



The Laminae are two broad plates of bone, which complete the vertebral 

 arch behind, inclosing a foramen which serves for the protection of the spinal 

 cord ; they are connected to the body by means of the pedicles. Their upper 

 and lower borders are rough, for the attachment of the ligamenta sub/lava. 



The Articular Processes, four in number, two on each side, spring from the 

 junction of the pedicles with the laminae. The two superior project upwards, 

 their articular surfaces being directed more or less backwards, the two inferior 

 project downwards, their articular surfaces looking more or less forwards. 1 



The /Spinous Process projects backwards from the junction of the two Iamina3, 

 and serves for the attachment of muscles. 



The Transverse Processes, two in number, project one at each side from the 

 point where the articular processes join the pedicle. They also serve for the 

 attachment of muscles. 



CHARACTERS OF THE CERVICAL VERTEBRA (Fig. 68). 



The Body is smaller than in any other region of the spine, and broader from 

 side to side than from before backwards. The anterior and posterior surfaces 



Fig. 68. A Cervical Vertebra. 



1 Jt may, perhaps, be as well to remind the reader, that the direction of a surface is determined 

 by thut of a line drawn at right angles to it. 



