[Stratum-structure of the spinal nerves in the understanding of body structure]

The main methodology employed in the progressive gross anatomy of today's Japan is typological anatomy (typologische Anatomie) as introduced by Seiho Nishi (1943; 1950; 1961). This typological methodology is sufficient to suggest the existence of a certain constancy between muscle phylogeny and innervation in spite of the classic theory of nerve-muscle specificity having been discredited. On the basis of findings obtained from the many recent Japanese studies including the author's study on the cervical plexus (Kida, 1987), it has been noted that the stratum-structure of the spinal nerves may be an important key for the phylogenetic understanding of animal body structure (Kida, 1988). 1) The stratum-structure of the spinal nerves was initially observed only in the limb plexus by Fürbringer (Schwalbe, 1981). At that time, it was accepted as the longitudinal strata corresponding to the portion occupied by nerve fibers to the flexors or the extensors (Bolk, 1902). This theory was effective for the systematic understanding of limb structure. 2) The stratum-structure of the spinal nerves was at first considered to be related to the concept of nerve-muscle specificity. After the review of Straus (1946) on the concept of nerve-muscle specificity, this concept was disproved and has since been generally regarded as a theory of the past, therefore stratum-structure is now treated independently of that concept. 3) However, recent Japanese studies have modified and progressed beyond the concept of the stratum-structure of the spinal nerves.(ABSTRACT TRUNCATED AT 250 WORDS)