CHAPTER VI 



ARTICULATIONS 



Articulations or joints. — The various bones of which the 

 skeleton consists are connected together at different parts of their 

 surfaces, and such connections are called articulations or joints. 



CLASSIFICATION 



Joints are classified as : — 



1. Synarthroses, or immovable joints. 



2. Amphiarthroses, or slightly movable joints. 



3. Diarthroses, or freely movable joints. 



In all instances some softer substance is placed between the bones, 

 uniting them together or clothing the opposed surfaces ; but the 

 manner in which the several pieces of the skeleton are thus con- 

 nected varies to a great degree. 



SYNARTHROSES, OR IMMOVABLE JOINTS 



The bones are connected by fibrous tissue or cartilage. 

 The bones of the cranium and the facial bones (with the ex- 

 ception of the lower jaw) have their adjacent surfaces ap- 

 plied in close contact, with only a thin 

 layer of fibrous tissue placed between their 

 margins. 



In most of the cranial bones this union 

 occurs by means of toothed edges which 

 dovetail into one another and form jagged 

 lines of union known as sutures. 

 orDE">n^TED.^SDTURE. ^lic thrcc most important sutures are as 

 follows : — 



(1) Coronal. — The line of union between the frontal and 

 parietal bones. 



(2) Lambdoidal. — The line of union betw^een the parietal and 

 occipital bones. 



82 



