LUMBAR VKKTEBR.B 15 



look backwards and in- J p^_ 9 * 



wards ; the inferior, con- 

 vex, and look forwards 

 and outwards. Project- 

 ing backwards and up- 

 wards from the supe- 

 rior articular process is 

 a short and flattened tu- 

 bercle or posterior trans- 

 verse process, and in a 

 strongly marked verte- 

 bra there is not unfre- 

 quently at the base of 

 this a smaller tubercle 

 which has a direction 



downwards. The last lumbar vertebra differs from the rest in 

 having the body very much bevelled posteriorly, so as to be broad 

 in front and narrow behind, and the transverse process thick and 

 large. 



General Considerations. Viewed as a whole, the vertebral column 

 represents two pyramids applied base to base, the superior being 

 formed by all the vertebrae from the second cervical to the last lum- 

 bar, and the inferior by the sacrum and coccyx. Examined more at- 

 tentively, it will be seen to be composed of four irregular pyramids, 

 applied to each other by their smaller extremities and by their bases. 

 The smaller extremity of the uppermost pyramid is formed by the 

 axis, or second cervical vertebra ; and its base, by the first dorsal. 

 The second pyramid is inverted ; having its base at the first dorsal, 

 and the smaller end at the fourth. The third pyramid commences at 

 the fourth dorsal, and gradually enlarges to the fifth lumbar. The 

 fourth pyramid is formed by the sacrum and coccyx. 



The bodies of the vertebrae are broad in the cervical region, nar- 

 rowed almost to an angle in the middle of the dorsal, and again broad 

 in the lumbar region. The arches are broad and imbricated in the 

 cervical and dorsal regions, the inferior border of each overlapping the 

 superior of the next ; in the lumbar region an interval is left between 

 them. A considerable interval exists between the cranium and atlas, 

 and another between the last lumbar vertebra and sacrum. 



The spinous processes are horizontal in the cervical, and become 

 gradually oblique in the upper part of the dorsal region. In the 

 middle of the dorsal region they are nearly vertical and imbricated, 

 and towards its lower part assume the direction of the lumbar spines, 

 which are quite horizontal. The transverse processes developed in 



* A lateral view of a lumbar vertebra. 1. The body. 2. The pedicle. 

 3. The superior intervertebral notch. 4. The inferior intervertebral notch. 

 5. The spinous process. 6. The transverse process. 7. The superior articular 

 processes. 8. The inferior articular processes. Q. The posterior transverse 

 process. 



