The morphological phenomenon of paravascular reorganization of nerve conductors.

The work is devoted to the study of a peculiar morphological phenomenon called paravascular reorganization of nerve conductors. In its most general form this phenomenon takes the form of a flattening and an enlargement of the nerve bundles which surround the vessel in the zones of their paravascular localization. The nerve fibres undergo a number of morphological changes, the most characteristic of which are: proliferation of Schwann elements, foci of "demyelinization", varicose swelling of axons, mesh-like formations in the axis-cylinders. These changes are seen mainly in the myelinated fibres of afferent origin. The unmyelinated vegetative fibres remain unchanged in the zones of paravascular localization. The phenomenon of paravascular reorganization of the nerve conductors is of wide-spread occurrence in mammals and humans. It is found most often in flat organs and tissues whose thinness results in contiguity of blood-supplying vessels and nerve conductors. The role of vascular mobility as factor in the morphological reorganization of nerve conductors at their points of intersection and contact within the vascular walls is discussed.