James Watson Kernohan was an Irish-American pathologist from County Antrim

County Antrim

County Antrim is one of six counties that form Northern Ireland, situated in the north-east of the island of Ireland. Adjoined to the north-east shore of Lough Neagh, the county covers an area of 2,844 km², with a population of approximately 616,000...

 , Ireland

Ireland

Ireland is an island to the northwest of continental Europe. It is the third-largest island in Europe and the twentieth-largest island on Earth...

. He studied medicine at Queen’s University, and in 1931 he emigrated to the United States and subsequently worked as a pathologist at the Mayo Clinic

Mayo Clinic

Mayo Clinic is a not-for-profit medical practice and medical research group specializing in treating difficult patients . Patients are referred to Mayo Clinic from across the U.S. and the world, and it is known for innovative and effective treatments. Mayo Clinic is known for being at the top of...

 in Rochester, Minnesota

Rochester, Minnesota

Rochester is a city in the U.S. state of Minnesota and is the county seat of Olmsted County. Located on both banks of the Zumbro River, The city has a population of 106,769 according to the 2010 United States Census, making it Minnesota's third-largest city and the largest outside of the...

. Kernohan retired from active medicine in 1962.

Kernohan is remembered for his work in neuropathology

Neuropathology

Neuropathology is the study of disease of nervous system tissue, usually in the form of either small surgical biopsies or whole autopsy brains. Neuropathology is a subspecialty of anatomic pathology, neurology, and neurosurgery...

, particularly research of spinal cord

Spinal cord

The spinal cord is a long, thin, tubular bundle of nervous tissue and support cells that extends from the brain . The brain and spinal cord together make up the central nervous system...

 tumors, brain abscesses and metastatic

Metastasis

Metastasis, or metastatic disease , is the spread of a disease from one organ or part to another non-adjacent organ or part. It was previously thought that only malignant tumor cells and infections have the capacity to metastasize; however, this is being reconsidered due to new research...

 brain lesions. He is credited with developing a widely used classification system for brain tumor

Brain tumor

A brain tumor is an intracranial solid neoplasm, a tumor within the brain or the central spinal canal.Brain tumors include all tumors inside the cranium or in the central spinal canal...

s. The eponymous Kernohan's notch

Kernohan's notch

Kernohan's notch is a cerebral peduncle indentation associated with some forms of transtentorial herniation . It is a secondary condition caused by a primary injury on the opposite hemisphere of the brain...

is named after him, which is a groove in the cerebral peduncle

Cerebral peduncle

Mainly, the three common areas that give rise to the cerebral peduncles are the cortex, the spinal cord and the cerebellum. The cerebral peduncle, by most classifications, is everything in the mesencephalon except the tectum. The region includes the midbrain tegmentum, crus cerebri and pretectum...

 caused by displacement of the brainstem against the incisura of the tentorium cerebelli

Tentorium cerebelli

The tentorium cerebelli or cerebellar tentorium is an extension of the dura mater that separates the cerebellum from the inferior portion of the occipital lobes.-Anatomy:...

 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 neurologist

Neurologist

A neurologist is a physician who specializes in neurology, and is trained to investigate, or diagnose and treat neurological disorders.Neurology is the medical specialty related to the human nervous system. The nervous system encompasses the brain, spinal cord, and peripheral nerves. A specialist...

Alfred Uihlein (1908–1990) he published Sarcomas of the Brain.