. Cunningham's Text-book of anatomy. Anatomy. STRUCTUKE OF JOINTS. 301 whose function it is to secrete a lubricating fluid, the synovia or joint-oil; (d) a plate of hyaline cartilage coating each of the opposing surfaces of the bones concerned. All the joints belonging to this group occur in the median plane of the body. It includes the symphysis pubis, the joints between the bodies of the vertebra?, and the joint between the manubrium sterni and the body of the sternum. A diarthrosis (Fig. 291) is the most elaborate as well as the most complete form of articulation. It is characterised by (a)
. Cunningham's Text-book of anatomy. Anatomy. STRUCTUKE OF JOINTS. 301 whose function it is to secrete a lubricating fluid, the synovia or joint-oil; (d) a plate of hyaline cartilage coating each of the opposing surfaces of the bones concerned. All the joints belonging to this group occur in the median plane of the body. It includes the symphysis pubis, the joints between the bodies of the vertebra?, and the joint between the manubrium sterni and the body of the sternum. A diarthrosis (Fig. 291) is the most elaborate as well as the most complete form of articulation. It is characterised by (a) capability of movement which is more or less free in its range; (6) a reduction of the uniting structures to a series of retaining lisa- ments ; (c) an articular cavity which is limited only by the surrounding ligaments; (d) the constant presence of synovial membrane; (e) cartilago articularis (hyaline encrusting cartilage) which clothes the opposed surfaces of the articulating bones. The majority of the joints in the adult belongs to this group. This series of joints has been subdivided into a number of minor sections, in order to emphasise the occurrence of certain well- marked structural features, or because of the particular nature of the movement by which they are characterised. Although in all diarthroses there is a certain amount of gliding movement between the opposed surfaces of the bones which enter into their formation, yet, when this gliding movement becomes their prominent feature, as in most of the joints of the carpus and tarsus, they are termed arthrodia. But bones may be articulated together so as to permit of movement in one, two, or more fixed axes of movement, or in modifications of these axes. Thus in uniaxial joints the axis of movement may lie in the longitudinal axis of the joint, in which case the trochoid rotatory form of joint results, as in the proximal and distal radio-ulnar articulations ; or it may correspond with the transverse axis of the artic
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectanatomy, bookyear1914
