THE COCCYGEAL JOINTS 



405 



THE COCCYGEAL JOINTS 



The sacro- coccygeal and inter -coccygeal articulations are con- 

 structed much after the same principle as the other vertebral articula- 

 tions. The coccygeal bones, however, are only united together by their 

 bodies. The anterior and posterior articulatory surfaces of each vertebra 



Fig. 43. — Articulations of the Lumbar Vertebr.b with the Sacrum. 



a. Last three lumbar vertebrae. 



B. Sacrum. 



C. C. Iliac bones. 



1. 1. Transverse process of fourth lumbar 



vertebra. 



2. 2. Transverse process of fifth lumbar vertebra. 



3. 3. Transverse process of sixth lumbar ver- 



tebra. 



4. 4. etc. Inferior common vertebral ligament. 



b. 5. Ligamentous fibres covering the capsules oe- 



tween the transverse processes of tlie fourth 



and fifth lumbar vertebrae. 



6. G. Capsular ligaments ssaiting together tlie fifth 



and sixth lumbar vertebrae. 



7. 7. Liimbo-sacral ligaments. 



8. S. Sacro-iliac ligaments. 



are both convex, and their inter-articular fibro-cartilage is hollow on both 

 surfaces. As to ligaments, they are i^epresented by bundles of longitudinal 

 fibres spread on the surfaces of these bones, which they envelop in a 

 common sheath. 



THE TEMPORO-MAXILLARY ARTICULATION 



The lower jaw articulates on each side by one of its condyles with 

 the glenoid cavity of the temporal bone. Between them is placed an 

 iMter- articular fibro-cartilage, with one synovial membrane above and 

 another below it. 



The articular surfaces above mentioned do not exactly fit one into the 

 other. This, however, is corrected thi'ough the interposition of a fibro- 

 cartilaginous disc between them. This disc represents an irregular plate, 

 flattened above and below, thicker in front than behind, moulded on each 



