Morphological and morphometric characterisation of Onuf's nucleus in the spinal cord in man
Open Access
- 1 August 1997
- journal article
- Published by Wiley in Journal of Anatomy
- Vol. 191 (2), 201-213
- https://doi.org/10.1046/j.1469-7580.1997.19120201.x
Abstract
In the absence of a systematic morphometric study of Onuf's nucleus in man, this investigation defines the limits of variation of segmental position and the range of length and volume of Onuf's nucleus in 6 normal humans displaying no neurological disease (2 males, 4 females). Serial section reconstruction methods in conjunction with the disector method provided information on the numbers, sizes and shapes of the constituent motor neurons of Onuf's nucleus. In contrast to previous descriptions, the cranial origin of Onuf's nucleus occurred in rostral S1 in 50% of subjects, and midcaudal S1 in the remaining subjects. Onuf's nucleus varied in length between 4 and 7 mm, and was 0.2-0.37 mm3 in volume. Differences in length or volume between males or females, or between the left and right side of the cord were not statistically significant. Neurons in Onuf's nucleus varied in diameter between 10 microns and 60 microns (mean 26 microns) and their mean number was 625 +/- 137. A higher density of neurons occurred at the cranial and caudal ends of the nucleus relative to the middle. While 37% of neurons were approximately spherical (shape index approximately 1), 44% were ellipsoid and 19% fusiform (shape indices varying between 0.26 and 0.8). These findings are compared with previous studies of Onuf's nucleus in man and animals. The results form a basis for further studies on Onuf's nucleus in normality and neurodegenerative diseases.This publication has 43 references indexed in Scilit:
- Estimate of the total number of neurons and glial and endothelial cells in the rat spinal cord by means of the optical disectorJournal of Comparative Neurology, 1993
- Changes in shapes of surviving motor neurons in amyotrophic lateral sclerosisBrain, 1993
- Ultra structure of pre‐synaptic input to motor neurons in Onuf's nucleus: controls and motor neuron diseaseNeuropathology and Applied Neurobiology, 1992
- A review of recent advances in stereology for quantifying neural structureJournal of Neurocytology, 1992
- Organization of afferent and efferent pathways in the pudendal nerve of the female catJournal of Comparative Neurology, 1989
- Quantitative synaptology of feline motoneurones to external anal sphincter muscleJournal of Comparative Neurology, 1988
- An ultrastructural study of cat lumbosacral γ-motoneurons after retrograde labelling with horseradish peroxidaseJournal of Comparative Neurology, 1985
- Somatostatin in the caudal spinal cord: An immunohistochemical study of the spinal centers involved in the innervation of pelvic organsJournal of Comparative Neurology, 1984
- A quantitative light microscopic study of the dendrites of cat spinal α‐motoneurons after intracellular staining with horseradish peroxidaseJournal of Comparative Neurology, 1981
- Differences between alpha and gamma motoneurons labeled with horse-radish peroxidase by retrograde transportBrain Research, 1976