[Anatomo-topographical and structural aspects of the dorsal nucleus (Clarke's nucleus) in humans]

There is fairly plentiful old and recemt literature on the dorsal nucleus (Clarke's nucleus), but the research reported is mainly in animals. The present study covers human material (9 spinal cords), considered mostly from the morphological-topographical aspects. In man, Clarke's column is not perfectly symmetrical, is "clublike" in shape, and reaches from the eighth cervical to the second lumbar segment. The left is slightly larger than the right. The large Clarke's cells typical of this nucleus are fewer in the cranial than in the caudal segments, with 14 percent more Clarke's neurons in the left-hand column. The staining methods used (Bielschowski, Weiger, Nissl) permitted topographical, overall and comparative study of the Clarke's neurons, revealing a thick layre of interneuronal and intra-columnar amyelin fibres dividing the nucleus thoracicus into two distinct zones. In conclusions, some morphological and functional hypotheses are put forward, based on the Author's observations.