HEAD AND NECK OF THE HORSE 



133 



A roomy joint capsule surrounds and encloses the opposed articular 

 surfaces. The tectorial^ memhrane (membrana tectoria) plays the 

 part of an interarcual ligament running from the arch of the epis- 

 tropheus to the margin of the dorsal arch of the atlas, and filling in 

 the considerable interarcual space between these bones. An inter- 

 spinal ligament can readily be distinguished as a double elastic band, 



Membrana tectoria. 



-Occipital bone. 



Membrana atlanto-occipitalis dorsalis. 

 Lig. laterale atlantis. 



Atlas. 



^ ,/:'!5W^ Capsula articularls. 



'"//■"mlL Lig. interspinale. 



41 



Epistropheus. 

 \\ \ 



'/; 



Capsula articularis. 



v^'-x Lig. interspinale. 



3rd cervical vertebra. 



Fig. 56.— The atlanto-occipital and allauto-epistropliic articulations. 

 Dorsal aspect. 



but it is with difficulty separated from the tectorial membrane. A 

 ventral ligament connects the mid-ventral ridge of the epistropheus 

 with the ventral tubercle of the atlas. A single flat band, correspond- 

 ing to the alar ligaments (ligaraenta alaria) of the dog, cat and pig, 

 will be found when the vertebral canal is opened at a later stage in the 

 dissection. 



The atlanto-occipital articulation (Articulatio atlanto- 

 occipitalis).— The occipital condyles and the fovea? of the atlas are so 



1 Tectum [L.], a roof. 



