LIGAMENTS OF THE RIBS, SPINE, ETC. 157 



Between this ligament and the vertebra, emerges the poste- 

 rior branches of the intercostal artery and nerve. The 

 posterior costo-transverse ligament extends from the tuber- 

 cle of the rib to the tip of the transverse process. 



The middle costo-transverse ligament can only be seen by a hori- 

 zontal section, made through the rib and transverse process, across 

 the vertebra. 



The middle, or interosseous transverse ligament, is a very 

 strong band, passing directly between the posterior surface 

 of the neck of the rib, and the surface of the transverse 

 process against which the rib rests. A synovial sac is 

 found between the tubercle of the rib and the transverse 

 process, except in the lower two ribs, where the tubercles 

 and transverse processes do not touch. 



The several vertebrae of the spinal column are united by 

 ligaments between their bodies and processes ; these cor- 

 respond throughout the column, except between the first 

 two vertebrae and the head ; these latter are described at 

 p. 74. 



The anterior common ligament is a broad glistening band 

 which reaches the whole length of the vertebral column; 

 it rests upon the front of the bodies of the vertebrae ; its 

 fibres run longitudinally, and are widest opposite the lum- 

 bar vertebrae. 



The posterior common ligament lies upon the posterior 

 aspect of the bodies of the vertebrae, within the vertebral 

 canal, reaching from the sacrum to the occipital bone ; its 

 fibres run longitudinally, and are in contact with the dura 

 mater ; it is widest opposite the cervical vertebrae, and as 

 it expands opposite each inter-vertebral disk, it has a scol- 

 loped outline along its borders. 



The inter-vertebral substance is displayed by separating 

 two vertebrae ; it lies between the contiguous surfaces of 

 their bodies, in the form of a circular disk, acting as a 

 " buffer" against the shocks to which the vertebrae would 

 otherwise be subject, and consists of a firm, outer, fibrous 

 portion, the layers of which are concentrically arranged, 

 and of a soft and elastic central portion, which bulges 

 when two vertebrae are cut apart, or sawn through longi- 

 tudinally. By separating the inter-vertebral substance 

 14 



