446 CERVICAL VERTEBRA. 



spinous, two for the transverse, and one for the upper and 

 lower surfaces of the body. 



The three primary centres present their ossific points 

 about the seventh or eighth week, those of the lateral por- 

 tions being observed a little in advance of the body, and at 

 birth the three pieces are found separate. In the first year 

 union begins with the lateral portions and at their poste- 

 rior part, where they come together to form the spinous 

 process, and during the third and fifth year with the body. 

 The osseous nuclei for the extremities of the spinous and 

 transverse processes, are seen about the fifteenth or six- 

 teenth year, and their union is not completed till the 

 twenty-fifth or thirtieth year. 



CERVICAL VERTEBRAE COMMON CHARACTERISTICS. 



A FIG. 124. B Thecervical vertebras occupy the 



superior portion of the column, are 

 seven in number, and are the 

 smallest in size. The superior sur- 

 face of each is concave from side 

 to side_, and bounded by a vertical 

 ridge; the lower surface is concave from before backward, 

 and has a ridge at the anterior edge. The lateral processes 

 are narrow and long, and bound a large and triangular 

 canal. 



The spinous process is bifid, short and horizontal. The 

 transverse is short and perforated at its basb by a foramen 

 for the passage of the vertebral vessels. Its upper surface 

 is grooved for the cervical nerves. 



FIG. 124, A represents the upper surface of a Cervical Vertebra. 1 Spinous 

 process bifurcated. 2 Lateral lamina. 3 Superior articular process. 4 Pos- 

 terior surface of body. 5 Transverse process bifurcated. 6 Anterior surface 

 of body. 7 Extremity of superior articular process. 8 Vertebral foramen 

 for spinal marrow. 



FIG. 124, B represents the lower surface of the same vertebra. 1 Spinous 

 process bifurcated. 3 Posterior root and notch of transverse process. 5 Bi- 

 furcation of transverse process, and the process showing a foramen in it for 

 giving passage to the vertebral artery. 6 Body of vertebra. 7 Inferior artic- 

 ular process. 4 Foramen for the spinal marrow. 



