444 



SPINAL COLUMN. 



FIG. 122. 



allowed to the cervical and lumbar 

 portions severally, and twelve to the 

 back, which is equal to the other 

 two together. 



Common characters of a vertebra, 

 Fig. 123. Each vertebra consists of 

 a body and processes. The body is 

 the anterior, thick, and middle por- 

 tion, of a cylindrical form and sym- 

 metrical. Its surfaces above and 

 below are flattened, convex in front 

 and concave behind. Its anterior 

 and posterior surfaces present nu- 

 merous foramina for the passage of 

 the vessels. 



The processes are nine in number, 

 two lateral, four oblique, two trans- 

 verse, and one spinous, which are 

 situated upon the back and lateral 

 parts of the body. The lateral, one 

 on each side, are seen to arise by a 

 pedicle from the posterior part of 

 the body. They proceed backward 

 in the form of an arch, expanding in 

 their course, forming the lateral 

 boundaries of the spinal canal, and 

 uniting posteriorly in the spinous 

 process. At the body these processes 

 are grooved superiorly and inferi- 

 orly into a notch, which, being ap- 

 plied to a corresponding notch in 

 the adjacent vertebra, is converted 

 into a foramen called the interver- 



Fi. 122 represents a side view of the Spinal 

 Column, with its curvatures and internal spongy 

 structure, a Atlas, b Dentata. c Seventh cer- 

 ^ I vical vertebra, d Twelfth dorsal vertebra, t 



Fifth lumbar. / First bone of the sacrum, g Last bone of sacrum, h Coccyx. 

 i Spinous process, j j Intervertebral foramina. 



