THE ARTICULATIONS IN GENERAL 



125 



when two opposing extremities are convex. It may be remembered that the 

 lateral tuberosities of each tibial surface present, for articulation with the 

 condyles of the femur, two convex diarthrodial faces whose coaptation is 

 rendered perfect by the interposition between each condyle and correspond- 

 ing tibial surface of a crescent-shaped fibro-cartilage, which for this reason 

 has been named a meniscus. In other joints these interarticular fibro- 

 cartilages are shaped like discs or biconcave lenses. There then result 

 double diarthroses : example, the temporo-maxillary articulation. (Fibro- 

 cartilage also covers bony surfaces over which tendons play, as on the 

 trochlear surface of the humerus, postero-inferior face of the navicular bone, 

 and elsewhere. In these situations it is named stratiform fibro-cartilage.^) 

 These organs are formed, as their name indicates, by fibrous and car- 

 tilaginous tissue ; their mode of association need not be referred to here, 

 though it may be observed that the cartilage is more particularly found in 

 all those points where there is most articular friction. They receive vessels, 

 and sometimes nerves. 



LIGAMENTS. These are bands which unite contiguous diarthrodial 

 surfaces. They are sometimes formed of white fibrous tissue, and some- 

 times of yellow ; from whence their division into two great classes of white 

 and yellow ligaments. 



a. The white ligaments are distinguished by the pearly whiteness of 

 their tissue and want of elasticity. Those which are found on the outer 



Fig 78 



Fig 79, 





WHITE OR NON-ELASTIC FIBROUS 

 TISSUE. 



YELLOW OR ELASTIC FIBROUS TISSUE, FROM 

 THE LIGAMENTUM NUCHJE. 



aspect of the articulations are termed peripheral, and those in their interior 

 are designated inter osseous or interarticular ligaments. 



The peripheral ligaments are generally composed of parallel fibres 

 collected in fasciculi, or spread out as membranes. In the first they are 

 called funicular, or ribbon-shaped; in the second, they are termed mem- 

 braniform, or capsular. The funicular ligaments constitute short, round, or 

 flattened bands, attached by their extremities to the two bones they unite ; 

 they are lined on their inner aspect by the synovial capsule, and covered 

 externally by tendons, aponeuroses, muscles, vessels, or nerves. The 

 capsular ligaments are often complete that is to say, they envelope the 

 whole articulation like a sack. At other times they are incomplete, and 



