ARTICULATIONS. 



Axis (Second Vertebra). This is characterized by a tooth- 

 like process (odontoid) ascending from the upper surface of 

 the body; it is constricted below and tapers bluntly above; 

 anteriorly it has an oval facet (for the anterior arch of the 

 atlas), and posteriorly, at its neck, a groove for the transverse 

 ligament. The anterior surface of the body has a raised trian- 

 gular surface ending above in a ridge. The pedicles are 

 grooved below but concealed above by the articular processes. 

 The laminae are thick, and end in a bifid spinous process which 

 is grooved below. The inferior articular processes follow the 

 cervical type: the superior are nearly flat and circular, and 

 look upward and slightly outward. The transverse process 

 turns down and is not bifid. [79] 



Vertebra Prominens (Seventh Vertebra). This is char- 

 acterized by its prominent spinous process, whose end is not 

 bifid. The transverse processes are longer than the others; 

 the vertebrarterial foramen is small, or absent. [80] 



ARTICULATIONS. 



Temporo-mandibular Joint. This is an arthrodial diar- 

 throsis between the condylar head of the mandible and the 

 articular part of the glenoid fossa of the temporal. The ar- 

 ticular surfaces are dissimilar in size and shape; the condylar 

 part is cylindrical with its long axis running outward and for- 

 ward; the glenoid part is concavo-convex antero-posteriorly 

 and includes the eminentia articularis. There is a complete 

 capsule (capsular ligament) whose outer wall is thickened (ex- 

 ternal lateral ligament) and divisible into anterior and posterior 

 portions attached above to the root tubercle and lower border of 

 the zygoma, and below to the outer side and posterior border 

 of the neck of the mandible; the fibres run downward and 

 backward. A horizontal interarticular fibro-cartilage (discus 

 articularis) divides the joint in two compartments ; its edges are 

 attached to the capsule; it is widest across, thickest behind, 

 and thinnest (often perforated) mesially. A synovial mem- 



[19] 



