2022 Volume 59 Issue 2 Pages 172-177
Toyokura’s remark on the “negative tetrads of ALS” made Mannen to begin the pathological investigations of the sacral anterior horn of the autopsied materials. He found the sparing of the Onuf ’s nucleus among the markedly depopulated anterior horn of the second sacral cord in ALS cases. He also found that the Onuf ’s nucleus is markedly depopulated in Shy-Drager syndrome with incontinence of urine and feces. Mannen’s discovery of the pathology of Onuf ’s nucleus in ALS and Shy-Drager syndrome was followed by numerous animal experiments using retrograde tracers injected in pelvic sphincter muscles and these experiments revealed unanimously that the neurons of the Onuf ’s nucleus are really innervating pelvic sphincter muscles. Our further investigations on the sacral cord in a case of rectal amputation showed the somatotopic localization of the somatic and autonomic efferent neurons innervating the external and internal anal sphincter muscles. Onuf ’s nucleus was described anatomically by Onuf but the functional significance of that nucleus was elucidated by Mannen, as a consequence this nucleus should be named Onuf-Mannen’s nucleus.
