28 FALSE VERTEBRAE. 



vical region, and gradually increase to the last lumbar. On either 

 side of the spinous processes, and extending the whole length of the 

 column, is the vertebral groove, which is shallow in the cervical, 

 and deeper in the dorsal and lumbar regions. It lodges the prin- 

 cipal 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 con- 

 cave curve is formed by the sacrum and coccyx. Besides the 

 antero-posterior curves a slight lateral curve exists in the dorsal 

 region, having its convexity towards the right side. 



Developement. The vertebra?, with the exception of the atlas, 

 axis, and vertebra prominens, are developed by three points of 

 ossification, one for each lamella, and one for the body. To these 

 are afterwards added six additional centres ; one for each trans- 

 verse process, two (sometimes united into one) for the spinous pro- 

 cess, and one for the upper and under surface of the body. The 

 atlas has five centres ; one (sometimes two) for the anterior arch, 

 one for each lateral mass, and two for the posterior arch. The 

 axis has five original centres ; one (sometimes two) for the body, 

 two for the odontoid process, and one for each lamella. The ver- 

 tebra prominens has likewise five ; one for the body, one for each 

 anterior segment of the transverse process, and one for each lamella. 



The ossification of the arches of the vertebra? commences from 

 above, and proceeds gradually downwards ; hence arrest of de- 

 velopement gives rise to spina bifida, generally in the loins. Ossi- 

 fication of the bodies, on the contrary, commences from the centre, 

 and proceeds from that point towards the extremities of the column ; 

 hence imperfection of the bodies occurs either in the upper or lower 

 vertebrae. 



Attachment of muscles. To the Mlas are attached ten pairs of 

 muscles : the longus colli, rectus anticus minor, rectus lateralis, 

 rectus posticus minor, obliquus superior and inferior, splenius colli, 

 levator anguli scapula?, first interspinous, and first intertransverse. 



To the axis are attached eleven pairs, viz : the longus colli, inter- 

 transversales, obliquus inferior, rectus posticus major, interspinales, 

 semi-spinalis colli, multifidis spina?, levator anguli scapulae, splenius 

 eolli, transversalis colli, and scalenus posticus. 



To the remaining vertebrce generally, thirty-two pairs ; viz. pos- 

 teriorly, the trapezius, latissimus dorsi, levator anguli scapula?, rhom- 

 boideus minor and major, serratus posticus superior and inferior, 

 splenius, sacro-lumbalis, longissimus dorsi, spinalis dorsi, cervicalis 

 ascendens, transversalis colli, trachelo-mastoideus, complexus, semi- 

 spinalis dorsi and colli, multifidus spina?, interspinales, supraspinales, 

 intertransversales, levatores costarum, anteriorly, the rectus anticus 

 major, longus colli, scalenus anticus and posticus, psoas magnus, 

 psoas parvus, quadratus lumborum, diaphragm, obliquus internus 

 and transversalis. 



