132 TOPOGRAPHICAL ANATOMY OF THE 



cervical vertebrtv are similar in their compouent parts to the articulations 

 between the thoracic vertebrte/ with the difference that there is no ventral 

 longitudinal ligament and supraspinal ligaments are absent. Inter- 

 vertebral fibro-cartUages (fibrocartilagines iutervertebrales), each con- 

 sisting of a fibrous ring and a pulpy nucleus, connect the bodies 

 of the vertebrae. Interarciial ligamnents (ligamenta fiava) pass 

 between the adjacent arches and are well developed and distinctly 

 elastic. Interspinal ligaments (ligamenta interspinalia) are developed 

 proportionate to the size of the spinous processes, and are elastic. 

 Intertransverse ligaments are absent. 



The joints between the articular processes of adjacent vertebrae 

 are provided with joint capsules (capsu]?e articulares), which are 

 more roomy in the neck than in other parts of the vertebral column in 

 accordance with the greater range of movement in this region. 



A dorsal longitudinal ligament will be exposed when the spinal 

 cord is removed from the vertebral canal. 



The special movements in the joints between the epistropheus and 

 the atlas and between the atlas and the occipital bone, and the con- 

 comitant peculiarities of the opposed bony surfaces, necessitates a 

 special arrangement of ligaments. 



The atlanto - epistrophic articulation (articulatio atlanto- 

 epistrophica). — This joint has an arrangement of bon\^ surfaces and 

 ligaments that permits of a rotation of the atlas - (and, with it, the 

 head), about an axis formed by the dens of the epistropheus.^ The 

 comparative looseness of adaptation of the bony surfaces, and the 

 elasticity of the interspinal ligament, render possible considerable 

 freedom of movement. 



The dissector should refresh his memory by referring to the bony 

 surfaces of the separated and macerated bones. The atlas carries two 

 saddle-shaped surfaces, separated by a wide dorsal and a narrow ventral 

 notch. In addition, the hinder pai't of the ventral half of the vertebral 

 foramen is hollowed from side to side to accommodate the dens of the 

 epistropheus. The epistropheus also has two saddle-shaped surfaces, 

 and the ventral face of the dens is smooth and convex from side to 

 side. If the bones be placed in apposition, it will be observed that 

 the amount of actual contact between them is very limited ; and, if 

 the normal movements of the joint be imitated, it will be noted that 

 the points of contact undergo a continuous series of changes. 



1 See The Topographiccd Anatomy of the Thorax and A bdomen. 



- "ArXas (Athis) [Gr.]. In Greek mythology, Atlas was one of the Titans and 

 bore the heavens on his shoulders, as the human atlas bone bears the skull. 



3 iin(TTpo(pei>s (epistropheus) [Gr.], the pivot. eTrta-Tpicpo} (eiDistvepho), to turn back 

 the head, to look back. 



