James Watson Kernohan
During his lifetime and a career spanning 42 years, James Watson Kernohan made numerous contributions to neuropathology, neurology, and neurosurgery. One of these, the phenomenon of ipsilateral, false localizing signs caused by compression of the contralateral cerebral peduncle against the tentorial edge, has widely become known as “Kernohan's notch” and continues to bear his name.
see Kernohan notch phenomenon.
The other is a grading system for gliomas from a neurosurgical viewpoint that continues to be relevant for grading of glial tumors 60 years after its introduction. In this paper, the authors analyze these two major contributions in detail within the context of Kernohan's career and explore how they contributed to the development of neurosurgical procedures 1).
James Watson Kernohan, M.D. (1896–1981) was an Irish-American pathologist born October 1, 1896 in County Antrim, Ireland. He studied medicine at Queen’s University, and in 1922 he emigrated to the United States and subsequently worked as a pathologist at the Mayo Clinic in Rochester, Minnesota. Kernohan retired from active medical practice in 1962 and died May 5, 1981.
Kernohan is remembered for his work in neuropathology, particularly research of spinal cord tumors, brain abscesses and metastatic brain lesions. He is credited with developing a widely used classification system for brain tumors. The eponymous Kernohan's notch is named after him, which is a groove in the cerebral peduncle caused by displacement of the brainstem against the incisura of the tentorium cerebelli in some cases of transtentorial herniation.
In 1952 he published an atlas of tumor pathology titled Tumors of the Central Nervous System, and with Mayo neurosurgeon Alfred Uihlein (1908–1990) he published Sarcomas of the Brain 2).
James Watson Kernohan has been recognized as the first neurosurgeon to report an intramedullary schwannoma case in 1952, though Wilder Penfield had already described an intramedullary lesion with schwannomas characteristics in 1932 3).