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ARTICULATIONS. 



1. THE LIGAMENTS OF THE BODIES. 



Anterior Common Ligament. Posterior Common Ligament. 



Intervertebral Substance. 



The Anterior Common Ligament (Figs. 183, 184, 191, 194') is a broad and 

 strong band of ligamentous fibres, which extends along the front surface of the 

 bodies of the vertebrae, from the axis to the sacrum. It is broader below than 

 above, thicker in the dorsal than in the cervical or lumbar regions, and some- 

 what thicker opposite the front of the body of each vertebra, than opposite the 

 intervertebral substance. It is attached, above, to the body of the axis by a 

 pointed process, which 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 inter- 

 vertebral substance, and the prominent margins of the vertebrae ; but less 

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

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

 to make the anterior surface of the spine more even. This ligament is com- 

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

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

 four or five vertebrae. A second subjacent set extend between two or three 

 vertebrae ; whilst a third set, the shortest and deepest, extend 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 (Figs. 183, 187) is situated within the spinal 

 canal, and extends along the posterior surface of the bodies of the vertebrae, 



Fig. 183. Vertical Section of two Vertebrae and their Ligaments, from the Lumbar Begion. 



from the body of the axis above, where it is continuous with the occipito-axoid 

 ligament, to the sacrum below. It is broader at the upper than at the lower 

 part of the spine, and thicker in the dorsal than in the cervical or lumbar 

 region. In the situation of the intervertebral substance and contiguous mar- 



