[Development, structure and myeloarchitectonics of the intraorganic nerves of the human hand muscles in infancy and childhood].

Twenty-two corpses of children (1-6 years of age) have been investigated. During the first year of life, certain manifested morphological changes take place in the innervation apparatus of the child hand muscles. The nerves are intensively growing in length, surpassing the muscles growth. With the development, some changes of the myelin transmitters spectrum occur: the number of fibers with large and middle diameter increases. This process is subjected to essential individual variations. Besides myelinization, the total number of fibers in the nerves increases, as well. By 6 years of age, the conductive part of the neural apparatus of the muscles studied reaches a rather high developmental level. The content of thick fibers in the toe muscle nerves makes more than 40%, the part of the middle fibers is also high. The muscles in the little finger mound leg behind in development of their nerves, the middle fibers prevail in them. Asynchronism in development is peculiar for nerves in some separate muscles. The correlation revealed for the main components of the neural fiber demonstrates that it is optimal in the toe muscle nerves. The little finger muscle nerves reach a high level of development, but the main mass of their fibers is still at the stage of maturing.