CHAPTER III 

 ARTICULATIONS 



It must be borne in mind that in osteology an articulation 

 is merely a union of two or more bones and may, or may not, 

 permit movement between the bones which form the articula- 

 tion; while the term joint usually refers to a movable articula- 

 tion. Unfortunately, there is seldom any distinction made 

 between the terms articulation and joint. 



The essential component parts of a movable joint are: (i) 

 Two or more bones. (2) Ligaments, usually with some kind of 

 cartilage. (3) Synovial membrane and synovial fluid. At 

 points of great friction, such as the knee joint, there are purse- 

 like sacs of connective tissue filled with fluid called bursae, 

 which are interposed between the articulating surfaces of the 

 bones and cartilaginous discs. The capsule of a joint is a 

 covering of fibrous connective tissue and is found in all joints, 

 except in some of the intracarpal and intratarsal, of man 

 (Sutton and Drinker). Man has thirteen bursae and ten 

 ligaments in his knee (Gray). The inner lining of the capsule 

 is formed by the synovial membrane which secretes synovial 

 fluid ("joint water") for lubricating and preventing friction 

 in the joint. 



All of the various kinds of articulations fall into three grand 

 divisions or classes: Synarthroses, immovable; amphiarthroses, 

 slightly movable; and diarthroses, freely movable joints. 



A. SYNARTHROSES, immovable articulations 



(a) Sutura, suture-hke, e.g., skull bones. 



(b) Gomphosis, conical process in socket, e.g., teeth. 

 (Gray, describes nine other types or sub-types of synarthroses.) 



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