Magnetic resonance imaging findings of Kernohan–Woltman notch in acute subdural hematoma (2022)


RegisterSign in


  • Access throughyour institution

Clinical Neurology and Neurosurgery

Volume 101, Issue 2,

June 1999

, Pages 122-124


Objective and importance: We report the case of a 73-year-old patient who presented a right motor deficit caused by an ipsilateral acute subdural hematoma. A magnetic resonance imaging (MRI) demonstration of Kernohan–Woltman notch phenomenon was obtained. Clinical presentation: The woman sustained a major head injury at home, followed by loss of consciousness. On admission to the emergency room, she was comatose, anisochoric (left>right), and showed a reaction to pain with decerebrating movements of left limbs (Glasgow Coma Scale (GCS) 4/15). A right severe hemiparesis was observed. Cerebral computed tomography scan showed a large right hemispheric subdural hematoma. Intervention and post-operative course: A wide right craniotomy was performed and the subdural hematoma evacuated. During the post-operative period, the level of consciousness gradually improved. A MRI performed about 2 weeks after operation showed a small area of abnormal signal intensity in the left cerebral peduncle. On discharge, the woman was able to communicate with others, but her right hemiparesis was still severe.


The compression of a contralateral cerebral peduncle against the edge of the tentorium caused by a supratentorial mass, with ipsilateral motor deficit, was first described by Kernohan and Woltman [1], who observed this phenomenon in a patient suffering from a right fronto-temporal brain tumor. Subsequently, several observations have been reported in patients with major head injury and brain tumors [2], [3], [4], [5], [6], [7], [8]. We describe a case of Kernohan–Woltman notch phenomenon (KWNP) secondary to acute post-traumatic subdural hematoma, in which the damage of contralateral cerebral peduncle has been verified by post-operative cerebral magnetic resonance imaging (MRI).

Section snippets

Case report

On going down the staircase in her home, a 73-year-old woman slipped along steps and sustained a severe head injury, immediately followed by loss of consciousness. On first neurological examination in the emergency room, she appeared to be comatose, with a Glasgow Coma Scale (GCS) of 4/15. Pupils were anisochoric (left>right) and a decerebrating reaction with left limbs was observed. A severe motor deficit on right hemisoma was also present. Cerebral computed tomography (CT) scan urgently


KWNP can be the cause of false localizing motor sign. The large right acute subdural hematoma observed in our patient produced an ipsilateral transtentorial uncal herniation and a compression of contralateral cerebral peduncle against the edge of the tentorium, with severe damage of the left corticospinal tract and a transient lesion of the Edinger–Westphal nucleus of the left third cranial nerve. The MRI performed 2 weeks after the operation confirmed this interpretation, revealing a small

References (11)

  • R.D. Zafonte et al.Kernohan–Woltman notch phenomenon: an unusual cause of ipsilateral motor deficit

    Arch Phys Med Rehabil


  • Kernohan JW, Woltman HW. Incisura of the crus due to contralateral brain tumor. Arch Neurol...
  • A.R. Cohen et al.

    Magnetic resonance imaging of Kernohan's notch



  • Y. Itoyama et al.

    Kernohan's notch in chronic subdural hematoma: findings on magnetic resonance imaging

    J Neurosurg


  • K.M. Jones et al.

    Ipsilateral motor deficit resulting from a subdural hematoma and a Kernohan notch

    Am J Neuroradiol


There are more references available in the full text version of this article.

Cited by (14)

  • Kernohan-Woltman notch phenomenon secondary to a cranial epidural hematoma

    2014, Revista Espanola de Anestesiologia y Reanimacion

    El fenómeno de la escotadura de Kernohan-Woltman es una manifestación neurológica paradójica que consiste en un déficit motor ipsilateral a la lesión cerebral primaria. Este fenómeno es causado principalmente por hematomas subdurales agudos o crónicos postraumáticos, siendo los hematomas epidurales una causa menos frecuente. Este fenómeno debe ser tenido en cuenta en casos de déficit motor ipsilateral, ya que puede resultar en procedimientos quirúrgicos del lado equivocado. Presentamos el caso de un paciente de 40 años quien, tras sufrir un traumatismo craneoencefálico, presentó disminución del nivel de conciencia y anisocoria. La tomografía computarizada de cráneo evidenció un hematoma epidural parietofrontal derecho con desplazamiento de la línea media y herniación uncal. Se realizó craneotomía y drenaje del hematoma y al sexto día del postoperatorio se evidenció una hemiparesia braquiocrural derecha. En la resonancia magnética se observó un área de isquemia capsulopeduncular izquierda acorde con el diagnóstico de fenómeno de la escotadura de Kernohan-Woltman.

    Kernohan-Woltman notch phenomenon is a paradoxical neurological manifestation which involves a motor deficit on the same side as the primary brain injury. It is produced mainly by acute or chronic subdural hematomas, and less frequently by post-traumatic epidural ones. It should be taken into consideration in cases of ipsilateral motor deficit, as it may lead to surgical procedures being performed on the incorrect side. We report the case of a 40 year old man who sustained a major head injury which was followed by a decreased level of consciousness and anisocoria. Computed tomography of the brain revealed a frontal and parietal epidural hematoma with right midline shift and uncal herniation. Craniotomy and drainage of the hematoma was performed, and on the sixth day after surgery it was observed that the patient had a brachio-crural right hemiparesis. Magnetic resonance imaging showed an ischemic area on the left capsule and cerebral peduncle consistent with the diagnosis of Kernohan-Woltman notch phenomenon.

  • Acute subdural hematoma after spinal anesthesia in an obstetric patient

    2008, Journal of Clinical Anesthesia

    Magnetic resonance imaging is useful in observing this phenomenon. There are various cases of subdural hematomas in the literature in which MRI detected hypodense lesions at T1 and hypertense lesions at T2 of the damaged cerebral peduncle lateral to the lesion [8-10]. Using transcranial electrical motor evoked potentials, Binder et al. [11] showed both a marked increase in voltage threshold as well as a reduction in the complexity of the motor evoked potential waveform on the hemiparetic side.

    Intracranial subdural hematoma is a serious complication of spinal anesthesia. We report the case of a 31-year-old woman who presented with headache and neurologic localizing signs after spinal anesthesia for cesarean delivery. She was subsequently diagnosed with a right temporoparietal subdural hematoma. The hematoma was evacuated, and she had good recovery.

  • Kernohan's notch phenomenon in chronic subdural hematoma: MRI findings

    2007, Journal of Clinical Neuroscience

    Although most commonly seen in this setting, several studies have also reported patients with traumatic head injury or spontaneous intracerebral accident with definitive evidence of Kernohan’s notch on MRI. The majority of reported cases have been related to acute space-occupying lesions such as a subdural hematoma,5–10 epidural hematoma,11,12 depressed skull fracture13 or spontaneous intracerebral hematoma.1,14,15 Only two patients with chronic subdural hematoma2,3 have been reported with MRI.

    We report two cases of Kernohan’s notch phenomenon secondary to chronic subdural hematoma detected by MRI. In the first case, the patient was drowsy with an oculomotor palsy and a hemiparesis ipsilateral to the chronic subdural hematoma. MRI in the post-operative period showed no abnormal signal or deformity of the crus cerebri. The neurological signs immediately resolved after trephination. In the second case, the patient was admitted with progressive decrease in their level of consciousness and ipsilateral hemiparesis with the chronic subdural hematoma. MRI on admission revealed an abnormal signal in the contralateral crus cerebri against the chronic subdural hematoma. After surgery, the mental state gradually recovered to normal with some degree of residual hemiparesis. In patients with chronic subdural hematoma, a compressive deformity of the crus cerebri, without abnormal signal on MRI, may predict a better neurological recovery in patients with Kernohan’s notch phenomenon.

  • Contralateral mesencephalic injury due to tentorial uncal herniation. Magnetic resonance imaging of the Kernohan's notch

    2004, Neurocirugia

    Presentamos un caso de hemiparesia ipsilateral a un hematoma extradural traumático, como consecuencia de la denominada “Hendidura de Kernohan” (Kernohan’s notch). Documentamos la lesión mediante imágenes axiales y coronales en resonancia magnética.

    We report a case of a traumatic epidural hematoma with ipsilateral hemiparesis, due to the so-called Kernohan’s notch. We document the injury with axial and coronal magnetic resonance imaging.

  • Kernohan–Woltman notch phenomenon: a review article

    2017, British Journal of Neurosurgery

View all citing articles on Scopus

Recommended articles (6)

  • Research article

    The microbiological diagnosis of tuberculous meningitis of Haydarpasa-1 study

    Clinical Microbiology and Infection, Volume 20, Issue 10, 2014, pp. O600-O608

    We aimed to provide data on the diagnosis of tuberculous meningitis (TBM) in this largest case series ever reported. The Haydarpasa-1 study involved patients with microbiologically confirmed TBM in Albania, Croatia, Denmark, Egypt, France, Hungary, Iraq, Italy, Macedonia, Romania, Serbia, Slovenia, Syria and Turkey between 2000 and 2012. A positive culture, PCR or Ehrlich-Ziehl-Neelsen staining (EZNs) from the cerebrospinal fluid (CSF) was mandatory for inclusion of meningitis patients. A total of 506 TBM patients were included. The sensitivities of the tests were as follows: interferon-γ release assay (Quantiferon TB gold in tube) 90.2%, automated culture systems (ACS) 81.8%, LÖwenstein Jensen medium (L-J) 72.7%, adenosine deaminase (ADA) 29.9% and EZNs 27.3%. CSF-ACS was superior to CSF L-J culture and CSF-PCR (p <0.05 for both). Accordingly, CSF L-J culture was superior to CSF-PCR (p <0.05). Combination of L-J and ACS was superior to using these tests alone (p <0.05). There were poor and inverse agreements between EZNs and L-J culture (Κ = −0.189); ACS and L-J culture (Κ = −0.172) (p <0.05 for both). Fair and inverse agreement was detected for CSF-ADA and CSF-PCR (Κ = −0.299, p <0.05). Diagnostic accuracy of TBM was increased when both ACS and L-J cultures were used together. Non-culture tests contributed to TBM diagnosis to a degree. However, due to the delays in the diagnosis with any of the cultures, combined use of non-culture tests appears to contribute early diagnosis. Hence, the diagnostic approach to TBM should be individualized according to the technical capacities of medical institutions particularly in those with poor resources.

  • Research article

    Design and rationale of TROCADERO: A TRial Of Caffeine to Alleviate DyspnEa Related to ticagrelOr

    Ticagrelor treatment has the side effect of increased incidence of dyspnea. Adenosine-induced dyspnea is augmented by ticagrelor and can be alleviated with the adenosine antagonist theophylline. Caffeine is a closely related xanthine derivative.

    The primary objective of the TROCADERO is to evaluate the effect of caffeine versus placebo on ticagrelor-associated dyspnea, measured by the visual analog scale area under the curve in patients with ongoing ticagrelor treatment after an acute coronary syndrome event.

    After a run-in period of 1 to 7 days of absence of caffeine intake, acute coronary syndrome patients with ticagrelor-induced dyspnea (planned inclusion 416) are randomized in a blinded fashion to either caffeine 200 mg twice daily or matching placebo with a treatment duration of 1 week. The primary efficacy end point is change in visual analog scale area under the curve for dyspnea, and the primary safety end point is occurrence of high on-treatment platelet reactivity measured by the VerifyNow P2Y12 assay.

    This trial will determine if adenosine antagonism by caffeine can alleviate ticagrelor-related dyspnea, without impairing the antiplatelet effect of ticagrelor.

  • Research article

    Intrapituitary mechanisms underlying the control offertility: key players in seasonal breeding

    Domestic Animal Endocrinology, Volume 56, Supplement, 2016, pp. S191-S203

    Recent studies have shown that, in conjunction with dynamic changes in the secretion of GnRH from the hypothalamus, paracrine interactions within the pituitary gland play an important role in the regulation of fertility during the annual reproductive cycle. Morphological studies have provided evidence for close associations between gonadotropes and lactotropes and gap junction coupling between these cells in a variety of species. The physiological significance of this cellular interaction was supported by subsequent studies revealing the expression of prolactin receptors in both the pars distalis and pars tuberalis regions of the pituitary. This cellular interaction is critical for adequate gonadotropin output because, in the presence of dopamine, prolactin can negatively regulate the LH response to GnRH. Receptor signaling studies showed that signal convergence at the level of protein kinase C and phospholipase C within the gonadotrope underlies the resulting inhibition of LH secretion. Although this is a conserved mechanism present in all species studied so far, in seasonal breeders such as the sheep and the horse, this mechanism is regulated by photoperiod, as it is only apparent during the long days of spring and summer. At this time of year, the nonbreeding season of the sheep coincides with the breeding season of the horse, indicating that this inhibitory system plays different roles in short- and long-day breeders. Although in the sheep, it contributes to the complete suppression of the reproductive axis, in the horse, it is likely to participate in the fine-tuning of gonadotropin output by preventing gonadotrope desensitization. The photoperiodic regulation of this inhibitory mechanism appears to rely on alterations in the folliculostellate cell population. Indeed, electron microscopic studies have recently shown increased folliculostellate cell area together with upregulation of their adherens junctions during the spring and summer. The association between gonadotropes and lactotropes could also underlie an interaction between the gonadotropic and prolactin axes in the opposite direction. In support of this alternative, a series of studies have demonstrated that GnRH stimulates prolactin secretion in sheep through a mechanism that does not involve the mediatory actions of LH or FSH and that this stimulatory effect of GnRH on the prolactin axis is seasonally regulated. Collectively, these findings highlight the importance of intercellular communications within the pituitary in the control of gonadotropin and prolactin secretion during the annual reproductive cycle in seasonal breeders.

  • Research article

    Comparison of parasite sequestration in uncomplicated and severe childhood Plasmodium falciparum malaria

    Journal of Infection, Volume 67, Issue 3, 2013, pp. 220-230

    To determine whether sequestration of parasitized red blood cells differs between children with uncomplicated and severe Plasmodium falciparum malaria.

    We quantified circulating-, total- and sequestered-parasite biomass, using a mathematical model based on plasma concentration of P. falciparum histidine rich protein 2, in Gambian children with severe (n=127) and uncomplicated (n=169) malaria.

    Circulating- and total-, but not sequestered-, parasite biomass estimates were significantly greater in children with severe malaria than in those with uncomplicated malaria. Sequestered biomass estimates in children with hyperlactataemia or prostration were similar to those in uncomplicated malaria, whereas sequestered biomass was higher in patients with severe anaemia, and showed a trend to higher values in cerebral malaria and fatal cases. Blood lactate concentration correlated with circulating- and total-, but not sequestered parasite biomass. These findings were robust after controlling for age, prior antimalarial treatment and clonality of infection, and over a realistic range of variation in model parameters.

    Extensive sequestration is not a uniform requirement for severe paediatric malaria. The pathophysiology of hyperlactataemia and prostration appears to be unrelated to sequestered parasite biomass. Different mechanisms may underlie different severe malaria syndromes, and different therapeutic strategies may be required to improve survival.

  • Research article

    Natural History of Infratentorial Intracerebral Hemorrhages: Two Subgroups with Distinct Presentations and Outcomes

    Journal of Stroke and Cerebrovascular Diseases, Volume 29, Issue 8, 2020, Article 104920

    Infratentorial intracerebral hemorrhage (ICH) is associated with worse prognosis than supratentorial ICH; however, infratentorial ICH is often excluded or underrepresented in clinical trials of ICH. We sought to evaluate the natural history of infratentorial ICH stratified by brainstem or cerebellar location using a prospective observational study inclusive of all spontaneous ICH.

    Using a prospective, single center cohort of patients with spontaneous ICH between 2008-2019, we conducted a descriptive analysis of baseline demographics, severity of injury scores, and long-term functional outcomes of infratentorial ICH stratified by cerebellar or brainstem location.

    Infratentorial ICH occurred in 82 (13%) of 632 patients in our ICH cohort. Among infratentorial ICH, cerebellar ICH occurred in 45 (55%) and brainstem ICH occurred in 37 (45%). Compared to cerebellar ICH, patients with brainstem ICH had significantly worse severity of injury scores, including lower admission Glasgow Coma Scale (median 14 [7.0 – 15.0] versus 4 [3.0 – 8.0], respectively; P < 0.001) and higher ICH Score (median 2 [1.0 – 3.0] versus 3 [2.75 – 4.0], respectively; P =  0.02). Patients with cerebellar ICH were more likely to be discharged home or to acute rehabilitation (OR 4.8, 95% CI 1.8 – 12.8) but there was no difference in in-hospital mortality (OR 0.4, 95% CI 0.1 – 1.1, P =  0.08) or cause of death (P =  0.5). Modified Rankin Scale scores at 3 months were significantly better in patients with cerebellar ICH compared to brainstem ICH (median 3.5 [1.8 - 6.0] versus median 6 [5.0 - 6.0], P =  0.03).

    Location of infratentorial ICH is an important determinant of admission severity and clinical outcome in unselected patients with ICH. Patients with cerebellar ICH have less severe symptoms at presentation and more favorable functional outcomes compared to patients with brainstem ICH.

  • Research article

    Hepatitis B Virus Mutant Infections in Hemodialysis Patients: A Case Series

    Kidney Medicine, Volume 1, Issue 6, 2019, pp. 347-353

    Hepatitis B virus (HBV) transmission in hemodialysis units has become a rare event since implementation of hemodialysis-specific infection control guidelines: performing hemodialysis for hepatitis B surface antigen (HBsAg)-positive patients in an HBV isolation room, vaccinating HBV-susceptible (HBV surface antibody and HBsAg negative) patients, and monthly HBsAg testing in HBV-susceptible patients. Mutations in HBsAg can result in false-negative HBsAg results, leading to failure to identify HBsAg seroconversion from negative to positive. We describe 4 unique cases of HBsAg seroconversion caused by mutant HBV infection or reactivation in hemodialysis patients.

    Following identification of a possible HBsAg seroconversion and mutant HBV infection, public health investigations were launched to conduct further HBV testing of case patients and potentially exposed patients. A case patient was defined as a hemodialysis patient with suspected mutant HBV infection because of false-negative HBsAg testing results. Confirmed case patients had HBV DNA sequences demonstrating S-gene mutations.

    Case patients and patients potentially exposed to the case patient in the respective hemodialysis units in multiple US states.

    4 cases of mutant HBV infection in hemodialysis patients were identified; 3 cases were confirmed using molecular sequencing. Failure of some HBsAg testing platforms to detect HBV mutations led to delays in applying HBV isolationprocedures. Testing of potentially exposedpatients did not identify secondary transmissions.

    Lack of access to information on past HBsAg testing platforms and results led to challenges in ascertaining when HBsAg seroconversion occurred and identifying and testing all potentially exposed patients.

    Mutant HBV infections should be suspected in patients who test HBsAg negative and concurrently test positive for HBV DNA at high levels. Dialysis providers should consider using HBsAg assays that can also detect mutant HBV strains for routine HBV testing.

View full text

Copyright © 1999 Elsevier Science B.V. All rights reserved.

You might also like

Latest Posts

Article information

Author: Neely Ledner

Last Updated: 06/13/2022

Views: 5989

Rating: 4.1 / 5 (62 voted)

Reviews: 93% of readers found this page helpful

Author information

Name: Neely Ledner

Birthday: 1998-06-09

Address: 443 Barrows Terrace, New Jodyberg, CO 57462-5329

Phone: +2433516856029

Job: Central Legal Facilitator

Hobby: Backpacking, Jogging, Magic, Driving, Macrame, Embroidery, Foraging

Introduction: My name is Neely Ledner, I am a bright, determined, beautiful, adventurous, adventurous, spotless, calm person who loves writing and wants to share my knowledge and understanding with you.