THE ARTICULATIONS IN GENERAL. 



171 



In the third, they are amphiarthroses, or mixed articulations; so termed 

 because they participate in the movements of the other two classes : synarthroses, 

 by the continuity established between the articular surfaces ; and diarthroses. by 

 the extensive motion they permit. 



The general characters that distinguish each of these three great classes of 

 articulations will be successively studied. 



Fig. 115. 



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rammiQ 



1^ 



PLANS OF THK DIFFERENT CLASSES OP ARTICULATIONS. 



A, Suture: 1, periosteum ; 2,sutural ligament. B, Amphiarthrosis : a, first degree— 1, periosteum; 

 2, articular cartilage ; 3, interarticular ligament : b, second degree — 4, single cavity in the 

 interarticular ligament : c, third degree — 5, double cavity in the interarticular ligament. C, 

 Diarthrosis: b, simple diarthrosis — 1, periosteum; 2, articular cartilage; 3, epithelial layer of 

 the synovial membrane (dotted line) ; 4, fibrous capsule ; 5, cul-de-sac of the synovial membrane ; 

 6, fibrous layer of the synovial membrane : c, double diarthrosis— 7, interarticular meniscus ; 8, 

 9, cavities of the two synovial membranes. 



General Characters of Diarthroses. 



"We ought to consider, in the diarthrodial articulations (Fig. 115, c, 6 and c) : 

 1. The contiguous boni/ surfaces which form them. 2. The cartilaginous layers 

 (cartilages of incrustation) which cover these. 3. The fibrous or fibro-cartilagi- 

 nous tissue {articular fihro-cartilages) which complete them, when they are not 

 shaped so as to be reciprocally adapted to each other. 4. The ligaments which 



