Syndesmology

SYNDESMOLOGY (syndesmologia), together with osteology, represents a branch of anatomy that deals with the motor apparatus, the passive part of the organs of movement. Academician Weitbrecht (1724) also used this term to designate the ligaments of internal organs. The science of joints (arthrology, arthrologia) examines not only joints in the strict sense of the word, but also cutaneous and cartilaginous connections in general (juncturae sceleti, s. ossium), which constitute the actual subject of that branch of anatomy called syndesmology in the literal sense. Both of these terms are of Greek origin: from syndesmos, which Hippocrates used to designate the connection of bones, and Galen used for ligaments; arthron means joint, and logos means doctrine. General syndesmology examines first of all the various types of bone connections: continuous ones, without the formation of intermediate cavities (synarthrosis), and interrupted ones due to the existence of a cavity (diarthrosis). The former are divided into cartilaginous (synchondrosis), formed by loose, fibrous, dense, or elastic connective tissue (syndesmosis simplex, s. elastica), as well as connections belonging to this type—sutures between the bones of the skull. Diarthroses, sometimes called true joints (Zernov), are subdivided into various types distinguished on the basis of the shape of the articular surfaces of the connected joints, depending on which there is a different character and scope of movements in them, to be examined in general syndesmology: joints can be flat, cylindrical, ginglymus (hinge), ovoid, saddle-shaped, spheroid (and the so-called "nut-shaped"), spiral, and irregular (both of the latter terms were proposed by Fick). Subsequently, descriptions are given of the individual constituent parts of joints: 1) articular cartilage, its extent, thickness, physical properties determining its significance, histological structure, as well as the intermediate intercalated cartilage (cartilago interarticularis); 2) articular capsule, its fibrous part, its relation to the muscles surrounding the joint, mucous bursae (also discussed in general and special myology), ligaments strengthening the joints and inhibiting movements in them, and other factors contributing to a more firm connection of skeletal parts (atmospheric pressure, tone and pull of contracting muscles); 3) articular cavity and its contents, synovia (smegma articulare, humor articularis), its physical properties, mechanical significance, formation, structure, and synovial membrane, its absorptive capacity, folds and villi present in it, so-called intra-articular ligaments, discs, menisci, changes in the volume of the articular cavity, its connection with surrounding bursae, etc. In addition to pure description, general syndesmology includes the examination of the functional significance of individual constituent parts of joints in a developed normal state, their variations depending on those of the muscular system and the trophic plasticity of skin and cartilage in the embryonic period as well as in the subsequent course of development, the onset of movements in joints, the formation of articular surfaces, and the changes in joints in phylogenesis. Finally, the methodology of examining joints in the living subject is indicated, of course in brief general terms.

P. Karuzin.