OSTEOLOGY 37 



Description. — ^The long cervical section of the spinal column is 

 S-shaped and is made up of fourteen vertebras. The anterior seg- 

 ments move freely forward, the middle ones backward and the pos- 

 terior ones forward, allowing the S-shaped curve of the neck. The 

 neck is flexible so that it is possible for the beak to reach the coccy- 

 geal oil gland. The bird is enabled to reach the feathers on all parts 

 of the body to cleanse and oil them. 



The Atlas. Location. — The first cervical vertebra is called the 

 atlas. Anteriorly it articulates with the single condyle of the oc- 

 cipital bone. Posteriorly it articulates with the axis, or second 

 cervical vertebra. 



Description. — The atlas is the smallest of the cervical vertebrae 

 and is ring-shaped. The anterior articular surface, half-moon 

 in shape, forms a deep articular cavity. The joint, called a ball- 

 and-socket joint, makes possible movements in all directions. The 

 condyle of the occiput also touches an articular end of the odontoid 

 process of the axis, or second cervical vertebra. Posteriorly there 

 projects from the atlas two small lateral wings possessing articular 

 facets which articulate with similar facets on the lateral wings of 

 the axis. Posteriorly the body of the atlas is also provided with an 

 articular surface which articulates with a similar surface on the 

 anterior portion of the body of the axis. 



The Axis. Location. — The axis is the second cervical vertebra. 

 It articulates anteriorly with the atlas, and by a facet on the extreme 

 anterior end of the odontoid process, with the condyle of the oc- 

 cipital bone. Posteriorly it articulates with the third cervical 

 vertebra. 



Description. — The body of the axis is short. The upper anterior 

 portion of the body of the axis is provided with a tooth-like process 

 called the odontoid process. There are two anterior lateral wings 

 provided with small articular facets which articulate with similar 

 facets of the atlas. The anterior surface of the body of the axis 

 forms a true articulation with the body of the atlas. 



The axis is provided with a superior and an inferior spine. There 

 are two posterior articular processes which articulate with the 

 prezygapophyses, or anterior articular processes, of the third cervical 

 vertebra. The posterior part of the body of the axis forms a true 

 articulation with the body of the third cervical vertebra. 



Other Cervical Vertebrae. — Beginning with the axis, the body 

 of which is relatively short, the body of each succeeding vertebra 



