16 VERTEBRAL COLUMN. 



their most rudimentary form in the axis, gradually increase in length 

 to the first dorsal vertebra. In the dorsal region they project obliquely 

 backwards, and diminish suddenly in length in the eleventh and 

 twelfth vertebrae where they are very small. In the lumbar region 

 they increase to the middle transverse process, and again subside in 

 length to the last. 



The transverse processes consist essentially of two parts, the ante- 

 rior of which in the dorsal region is the rib, while the posterior retains 

 the name of the transverse process. In the" cervical region these 

 two elements are quite apparent, both by their different points of at- 

 tachment to the vertebra, and by the vertebral foramen which divides 

 them at their base. In the lumbar region the so-called transverse 

 processes are, in reality, lumbar ribs, while the transverse processes 

 will be found behind them in a rudimentary state, developed like the 

 true transverse processes in the cervical region, from the superior ar- 

 ticular processes. When the anterior and posterior transverse pro- 

 cesses are examined in relation with each other, they will be observed 

 to converge ; and if the latter were prolonged they would unite as in 

 the cervical region and enclose a foramen, or they would rest in con- 

 tact as in the dorsal region, or become consolidated as in the forma- 

 tion of the sacrum. Moreover, the posterior transverse processes are 

 directed upwards, and if they were prolonged, they would come into 

 contact with a small tubercle which is found at the base of the poste- 

 rior transverse process (in strongly marked vertebrae) in the vertebra 

 above. This junction would form a posterior intervertebral foramen, 

 as actually occurs in the sacrum. In brief, the lumbar vertebrae ex- 

 hibit those transitional changes which are calculated, by an easy gra- 

 dation, to convert separate vertebrae into a solid bone. The transverse 

 processes of the eleventh and twelfth dorsal vertebrae are very inte- 

 resting in a transcendental point of view, as exhibiting a tendency 

 which exists obscurely in all the rest, namely, to trifurcate. Now, 

 supposing these three branches to be lengthened in order to fulfil their 

 purposes, the anterior would constitute the articulation or union with 

 a rib, while the superior and inferior would join similar branches in 

 the vertebra above and below, and so form the posterior intervertebral 

 foramen. 



The intervertebral foramina formed by the juxta-position of the 

 notches, are smallest in the cervical region, and gradually increase to 

 the last lumbar. On either side of the spinous processes, and extend- 

 ing the whole length of the column, is the vertebral groove, which is 

 shallow and broad in the cervical, and deeper and narrower in the 

 dorsal and lumbar regions. It lodges the principal muscles of the 

 back. 



Viewed from the side, the vertebral column presents several curves, 

 the principal of which is situated in the dorsal region, the concavity 

 looking forwards. In the cervical and lumbar regions the column is 

 convex in front ; and in the pelvis an anterior concave curve is formed 

 by the sacrum and coccyx. Besides the antero-posterior curves, a 



