The role of nerves in the developing vertebrate limb: a teratogenic plea for re-evaluation
Roth, M.
Folia Morphologica 23(4): 357-374
1975
ISSN/ISBN: 0015-5640 PMID: 1205429 Document Number: 95894
Topographical relationships of bones and nerves in teratogenic micromelia suggest that the osteo-neural growth relationship responsible for the morphogensis of the neurocranium works in the axial and appendicular skeleton as well, irrespective of the different histogenesis of bone tissue. Normal and pathological morphogenetic features of skeletel elements such as their length, curvatures and terminal expansion are determined by the amount of space available along the spinal cord and/or the peripheral nervous trunks. According to the physiological or pathologically enhanced growth retardation of the peripheral nervous trunks, the gross morphology of bones assumes normal or pathological features as well. The vertebrate body may be conceived as composed of the extremely dense network of neural extensive growth filled-in with the other (mostly mitotically growing) tissues. Although capable of existing quite independently, for instance in the tissue explant, the most intricate meshing and interdependence of the 2 growth types within the living body appears absolutely indispensable for complete development. Those cells which during development do not enter into a relationship with the extensive neural network are doomed to death, for instance the interdigital cellular messes in embryogenesis of the hand or foot. Teratogenic oligo-, polyor syndactyly may result from a faulty primary arrangement of the extensive neural network within the developing hand or foot plate. The development of the limb bud is closely linked to the development of it nervous structures. This highly elusive developmental relationship is difficult to study in the early developmental stages, especially under the pathological conditions of gross teratogenic skeletal deformities. The aneurogenic development of the limb bud is not necessarily opposed to this relationship since denervation represents an unnatural state.