Kernohan’s Notch

James Collier, in 1904, gave one of the best early accounts of tonsillar herniation as a terminal event caused by raised intracranial pressure. He also observed false localizing signs. Adolf Meyer added to the picture, describing detailed pathology of tentorial and subfalcial herniation, and hemianopia as a false localizing sign. In 1929, Kernohan and Woltman published their important work on ipsilateral hemiplegia accompanying expanding brain lesions. They demonstrated grooving of the crus cerebri on the side opposite to a tumour. Jefferson devised the term ‘the tentorial pressure cone.’ The current debate about the mechanisms is indicated in this short review. Copyright © 2006 S. Karger AG, Basel The clinical signs of imminent death seen in terminal brain tumours, abscesses and haematomata had been variably recognised though not understood from the time of Wepfer’s account of cerebral haemorrhage [1] . The consequences of raised pressure within the skull were however only appreciated in the early 20th century. One of the first references to the causal brain herniation was that of James Collier [2] , who clearly described cerebellar tonsillar herniation in 1904. He observed accomReceived: March 1, 2006 Accepted: March 2, 2006 Published online: June 14, 2006 J.M.S. Pearce 304 Beverley Road Anlaby, East Yorks HU10 7BG (UK) © 2006 S. Karger AG, Basel 0014–3022/06/0554–0230$23.50/0 Accessible online at: www.karger.com/ene D ow nl oa de d by : 54 .7 0. 40 .1 1 11 /2 7/ 20 17 1 2: 22 :2 8 P M