THE LIGAMENTS OF THE ATLAS AND AXIS. 



709 



The posterior occipito-atlantal ligament (fig. 252, *) is a thin broad Posterior 



membrane, the deep surface of which is intimately united to the between 



occipital 

 bone and 

 atlas, 



FIG. ii52. EXTERNAL LIGAMENTS BEHIND BETWEEN THE OCCIPITAL BONE. 

 ATLAS, AND Axis. 



1. Posterior occipito-atlantal liga- 

 ment. 



2. Posterior atlanto-axial. 



3. Vertebral artery entering be- 

 neath the occipito-atlantal ligament. 



dura mater. It is attached above to the hinder margin of the 

 foramen magnum of the occipital bone, and below to the posterior 

 arch of the atlas. Behind the upper articular process of the altas 



FIG. 253. INTERNAL LIGAMENTS BETWEEN THE OCCIPITAL BONE, ATLAS, 

 AND Axis. First view. (Bourgery.) 



1. Long occipito- axial ligament. 



2. Beginning of the posterior common ligament. 



it forms an arch over the groove of the bone in this situation, 

 bounding with the latter an aperture through which the vertebral 

 artery and the suboccipital nerve pass. 



