

THE CERVICAL VERTEBRA 







rough, and give attachment to the intervertebral fibrocartilages, and each presents 

 a rim around its circumference. In front, the body is convex from side to side 

 and concave from above downward. Behind, it is flat from above downward 

 and slightly concave from side to side. Its anterior surface presents a few small 

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

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

 vertebral veins from the body of the vertebra. 



Pedicles (radices arci vertebra). The pedicles are two short, thick processes, 

 which project backward, one on either side, from the upper part of the body, 

 at the junction of its posterior and lateral surfaces. The concavities above and 

 below the pedicles are named the vertebral notches; and when the vertebra? are 

 articulated, the notches of each contiguous pair of bones form the intervertebral 

 foramina, already referred to. 



Laminae. The laminae are two broad plates directed backward and medialward 

 from the pedicles. They fuse in the middle line posteriorly, and so complete the 

 posterior boundary of the vertebral foramen. Their upper borders and the lower 

 parts of their anterior surfaces are rough for the attachment of the ligamenta 

 flava. 



Processes. Spinous Process (processus spinosus). The spinous process is 

 directed backward and downward from the junction of the laminae, and serves 

 for the attachment of muscles and ligaments. 



Articular Processes. The articular processes, two superior and two inferior, 

 spring from the junctions of the pedicles and laminae. The superior project 

 upward, and their articular surfaces are directed more or less backward; the 

 inferior project downward, and then- surfaces look more or less forward. The 

 articular surfaces are coated with hyaline cartilage. 



Transverse Processes (processes transversi). The transverse processes, two in 

 number, project one at either side from the point where the lamina joins the 

 pedicle, between the superior and inferior articular processes. They serve for 

 the attachment of muscles and ligaments. 



Structure of a Vertebra (Fig. 83). The body is composed of cancellous tissue, covered by 

 a thin coating of compact bone; the latter is perforated by numerous orifices, some of large size 

 for the passage of vessels; the interior of the bone is traversed by one or two large canals, for the 

 reception of veins, which converge toward a single large, irregular aperture, or several small 

 apertures, at the posterior part of the 

 body. The thin bony lamellae of the 

 cancellous tissue are more pronounced 

 in lines perpendicular to the upper 

 and lower surfaces and are developed 

 in response to greater pressure in this 

 direction (Fig. 83). The arch and 

 processes projecting from it have 

 thick coverings of compact tissue. 





The Cervical Vertebrae (Verte- 

 bras Cervicales). 



FIG. 83. Sagittal section of a lumbar vertebra. 



The cervical vertebras (Fig. 

 84) are the smallest of the true 

 vertebrae, and can be readily 



distinguished from those of the thoracic or lumbar regions by the presence of a 

 foramen in each transverse process. The first, second, and seventh present excep- 

 tional features and must be separately described; the following characteristics are 

 common to the remaining four. 



The body is small, and broader from side to side than from before backward 

 The anterior and posterior surfaces are flattened and of equal depth; the former 



