De segmentale innervatie van romp en ledematen bij de mens

Although the editor, in his introduction, does not make it quite clear why at this particular point in time the decision was taken to reprint Louis Bolk's neuro-anatomical work on the segmental innervation ofthe human trunk and limbs, there can be no doubt that this monograph of 1910, both from a clinical and historical point of view, is a worthwhile publication. Bolk, the most influential of Dutch anatomists during the first half of the twentieth century, was highly regarded for his educational methods and played a decisive role in establishing research institutions of lasting importance, such as the Central Dutch Institute for Brain Research. Clinicians today can find much of interest in the present text since the concept of segmental divisions as applied to the peripheral nervous system still has its place in the examination of neurological patients, and the "facts" of it have changed surprisingly little since Bolk's time. Historically speaking, the text forms in tone and outlook an example of the path trodden by comparative anatomists once Darwin's evolutionary theory had got a stronger hold on them. They concerned themselves with the question how the development of the human individual might reflect the evolutionary past of the different species (or, in Ernst Haeckel's terms, how "Ontogeny recapitulates phylogeny"). Bolk (1866-1930), who studied anatomy under Georg Ruge (1852-1919), in his turn a disciple of the Jena professor Carl Gegenbaur (1826-1903), showed in his early work on metamerology a clear influence of the latter's school of thought: placing comparative anatomy on the frontlines in the search for understanding the evolution of species. Between 1894 and 1900, Bolk published the results of his work in Gegenbaur's Morphologisches Jahrbuch. The 1910 monograph under discussion is a summary of the findings of those years. Bolk considered higher developed vertebrates to have "lost" the direct visibility of their principal-and in embryological stages still discernible-building elements, which he called segments. This loss was due to their development of more differentiated organ-systems. But, so he states, it is still possible indirectly to trace back this rostro-caudal segmental origin by accurately dissecting the peripheral nervous system, since in this system, especially when looking at the spinal nerves, the segmentation principle is clear. The next step was to describe the innervation of muscles and skin, and, following the nervous system, to divide also these tissues into their primary myotomes and dermatomes. That his interest was also of a …