Subdural hematoma (SDH) is usually secondary to mechanical trauma. Spontaneous subdural hematoma is still rare with unclear pathophysiology. The classic findings of subdural hematoma is sudden drop in mental status, an ipsilateralmydriasis with contralateral hemiparesis. However SDH can sometimes compress the contralaterl corticospinal tract resulting in ipsilateral motor weakness, this phenomenon is known as Kernohan-Woltman Notch Phenomenon.
Ahmed, Fareed; Shahzad Shamim, Muhammad; and Asad Ali, Sidra
"Kernohan–woltman notch phenomenon:Case report and Review of literature,"
Pakistan Journal of Neurological Sciences (PJNS): Vol. 12:
3, Article 8.
Available at: https://ecommons.aku.edu/pjns/vol12/iss3/8