186 



THE A R Tim A TIOXS 



Tlie transverse ligament (lijrs. 195, li)G, and 108) is one of the most important 

 structures in the Ixxly, for on its integrity and that of the check hgaments our hves 

 largely depend. It is a thick and very strong hand, as dense and closely woven as 

 tibro-cartilage, al)Out a quarter of an inch (6 mm. ) deep at the sides, and somewhat 

 more in the middle line. Attached at each end to a tubercle on the inner side of 

 the lateral mass of the atlas, it crosses the ring of this bone in a curved manner, so 

 as to have the concavity forward; thus dividing the ring into a smaller anterior por- 

 tion for the odontoid process, and a larger posterior part for the spinal cord and its 

 mem])ranes, and the spinal accessory nerves. It is flattened from before backwards, 

 l)eing smooth in front, and covered by synovial meml)rane to allow it to glide freely 

 over the posterior facet of the odontoid process. Where it is attached to the atlas 



Fig. 195.— Vektical Anteeo-postekior Section of Spinal Column through Median 



Line, showing Ligaments. 



Left lateral 

 odontoid 

 ligament 



Aseendi 

 portion 



crucial 

 ligament 



Transverse ligament 



Inner part of capsular ligament 

 of occipito-atlantal joint 



Posterior occipito-atlantal 

 ligament 



Descending portion of crucial 

 ligament 



Posterior atlanto-axoidean 

 ligament 



Interspinous ligament 



Ligaraentum subflavum 



Central odontoid 



ligament 

 Anterior occipito- 

 atlantal ligament 



Allan to-odontoid 

 synovial sac 



Anterior atlanto- 

 axoideau ligament 



it is smooth and well rounded off to provide aneasvfloorof communication between 

 the transverso-odontoid and occiijito-atlantal joints. 



To its i)osterior sin-face is added, in the middle line, a strong fasciculus of 

 vertical fibres, passing upwards from the root of the odontoid process to the basilar 

 border ot the foramen magnum on its cranial aspect. Some of these fibres are 

 derived from the transverse ligament. These vertical fibres give the transverse 

 ligament a cruciform appearance; lience the name, the crucial ligament ffiss 195 

 and 198) applied to tlie wliolc. ^ ^ " 



The atlanto-odontoid capsular ligament (fig. 196) is a tough, loose mem- 

 brane, comi)letely surrounding tlie apposed articular surfaces of the atlas and 

 odontoid process. At the odontoid process it blends above with the front of the 



