"The phenomenon was described by James Watson Kernohan (1896-1981), an Irish-born American pathologist in 1929 after an autopsy study revealed a notched cerebral peduncle from a contralateral herniation syndrome 5."
"Transtentorial herniation is a well-described neurologic phenomenon caused by an expanding supratentorial mass lesion or haemorrhage. Uncal herniation is a common subtype of transtentorial herniation in which the innermost part of the temporal lobe, the uncus, is displaced beyond the free edge of the tentorium and exerts pressure on the brainstem, most notably the midbrain."