CHAP, in.] SKELETON OF THE HEAD AND TRUNK. 53 



thus tends, by filling up depressions, to render the surface of the 

 vertebral column more even. 



Another band of fibres, called the dorsal common ligament, passes 

 backwards within the neural canal along its ventral surface from the 

 skull backwards. 



Each pair of articulating zygapophyses is surrounded and enclosed 

 by a fibrous bag, the fibres passing from one zygapophysis to the 

 other. Such a surrounding and enclosing membrane is termed a 

 capsular ligament. Enclosed within the capsular ligament is a 





Fig. 20. INTERVERTEBRAL Discs. 



A. Surface view enlarged. 



B. Section through two discs. 

 /. Lamellse. 



(/. Soft central portion. 

 I. Interspinous ligaments. 



membrane which secretes an albuminous fluid termed synovia. 

 Membranes of the kind are therefore termed synovial, and are 

 placed between hard parts which are destined to move one on the 

 other. Synovial membranes will be more fully noticed in the descrip- 

 tion of the different kinds of joints at the end of the next chapter. 



Certain ligaments with much yellow elastic tissue, called the liga- 

 menta subflava, pass between the neural lamina, being attached to the 

 inner or ventral surface on one neural lamina and thence passing 

 backwards to the anterior margin of the neural lamina next behind. 

 They are thus best seen when the neural arches are removed and 

 viewed on their ventral aspect. 



