ARTICULATIONS OF THE VERTEBRAL COLUMN 



269 



above, to the body of the axis by a pointed process, where it is continuous with {he 

 anterior atlanto-axial ligament, is connected with the tendon of insertion of the 

 Longus colli muscle, and extends down as far as the upper bone of the sacrum. 

 It consists of dense longitudinal fibres, which are intimately adherent to the 

 intervertebral substance and the prominent margins of the vertebra 3 , but less 

 closely to the middle of the bodies. In the latter situation the fibres are exceed- 

 ingly thick, and serve to fill up the concavities on their front surface and to make 

 the anterior surface of the vertebral column more even. This ligament is com- 

 posed of several layers of fibres, which vary in length, but are closely interlaced 

 with each other. The most superficial or longest fibres extend between four or 

 five vertebra?. A second subjacent set extends between two or three vertebra?, 

 while a third set, the shortest and deepest, extends from one vertebra to the next. 

 At the side of the bodies the ligament consists of a few short fibres, which pass 

 from one vertebra to the next, separated from the median portion by large oval 

 apertures for the passage of vessels. 



The posterior common ligament (ligamentum longitudinale posterius~) (Figs. 

 227 and 228) is situated within the vertebral canal, and extends along the posterior 

 (dorsal) surface of the bodies of the vertebrae from the body of the axis above, where 



INTERVEHTE- 

 B RAI- FIBRO- 

 CARTILAGE 



ROOT OF 



VERTEBRAL 



ARCH 



FIG. 221. Intervertebral disk, with the adjacent 

 vertebral bodies, from in front. (Spalteholz.) 



POSTERIOR COMMON 

 LIGAMENT 



FIG. 220. Vertebral bodies with ligaments, from 

 behind. (Spalteholz.; 



it is continuous with the posterior occipito- 

 axial ligament, to the sacrum below. It is 

 broader above than below, and thicker in 

 the thoracic than in the cervical or lumbar 

 regions. In the situation of the interver- 

 tebral substance and contiguous margins 

 of the vertebrae, where the ligament is more intimately adherent, it is broad, and 

 presents a series of dentations with intervening concave margins; but it is narrow 

 and thick over the centre of the bodies, from which it is separated by the vena? 

 basis vertebra?. This ligament is composed of smooth, shining, longitudinal 

 fibres, denser and more compact than those of the anterior ligament, and formed 

 of a superficial layer occupying the interval between three or four vertebra?, and 

 of a deeper layer which extends between one vertebra and the next adjacent 

 to it. It is separated from the dura of the spinal cord by some loose connective 

 tissue, which is very liable to serous infiltration. 



The Intervertebral Fibrocartilages (fibrocartilagines intervertebrales) (Figs. 

 221 and 222). Each fibrocartilaginous disk is of lenticular form and of composite 



