iOO 



THE ANATOMY OF THE HORSE 



lateral border of the arch of the atlas, and ai^e attached to the sides of thj 

 condyles of the occiput, or rather between the condyles and the styloM 

 processes. 



The long inferior ligament arises from the tubercle on the inferior surface 

 of the atlas, and is attached to the basilar process of the occiput. 



The short inferior ligament arises from the tubercle on the inferior sui'face 

 of the atlas, is attached to the foramen magnum of the occiput, and is con- 

 nected with the theca vertebralis. 



A thin fibrous ligament (the occipito-atlo'ul) surrounds the entire articula- 

 tion ; it is attached anteriorly to the condyles of the 

 occiput, and posteriorly to the articulatory surface of 

 the atlas. This membrane is thin and clastic in- 

 feriorly ; superiorly it is formed of two bundles of 

 fibres, which cross one another like the letter X. 

 Internally it is lined by synovial membrane. 



The axis, or vertebra deJjtata, is united to the 

 atlas, and partially also to the occiput, as follows : — 



1. Articular surfaces are formed on tlie odontoid 

 process of the axis, and also on the sides of its body 

 close to the root of that part. These correspond 

 with similar faces on the inside of the ring of the 

 atlas, and also on its posterior side. 



2. The ligaments connecting the rings of the tiro 

 vertebrce together, or the srq^erior and inferior alio- 

 axoid ligaments. The former represent the inter- 

 spinous ligaments of the other vertebrse — being yellow, 

 elastic, and formed of two layers, which are con- 

 tinuous with the capsular ligaments — the latter is a 

 large thin band, which is stretched from the infei'ior 

 face of the axis to the inferior spine of the atlas, 

 lying concealed by the longus colli muscle. Besides 

 these two ligaments, there is also a capsular liga- 

 ment, which commences from the sides of the 

 superior atlo-axoid ligament, and after uniting with 

 the borders of the odontoid ligament is confounded 

 with the fibres of the inferior atlo-axoid. In fact, 

 it is a mesh of white fibrous tissue connecting the 

 three together. 



3. The odontoid ligaments, which are covered by 

 the superior atlo-axoid ligament. On cutting through 

 these the following sets of fibres will be made apparent : — First, a transverse 

 band arises from the root of the odontoid process, and dividing into two like 

 the letter V, is attached on each side to the ridge on the inferior part of the 

 fin"- of the at'las, a few thin fibres passing on to be attached to the basilar 

 process and condyles of the occiput. Secondly, a strong band arises from 

 the point of the odontoid process, and is attached to the middle of the ridge 

 on the inferior part of the atlas. Thirdly, a few fibres pass across from the 

 inside of the ring of the atlas on one side to the corresponding part of the 

 other. These serve to strengthen tlie capsule, but they luavr; not the sub- 

 itanco of the corresponding ligament in th 5 human fiaiio. 



Fia. 30.— Superior View of 

 THE Joints roRMEn be- 

 tween TUB First Tw» 

 Vertebr.« of the Neck 



AND BETWEEN THE ATLA3 



AND Occiput. 



a. Superior fibres of the occi- 



pito-atloid ligament. 

 H. Atlas. 

 C. Vertebra dentata, showing 



the superior atlo-axoid 



ligament. 

 1>. Third cervical vertebra. 

 1'. K. Transverse processes 



ofdentata. 

 1. 1. Odontoid ligament. 



