Topics

Topic

design image
Uncus

The uncus is a prominent, hook-shaped structure located on the medial surface of the temporal lobe, forming part of the anterior parahippocampal gyrus. It is situated at the anterior end of the hippocampal formation and is closely related to the amygdala. Clinically, the uncus is notable for its involvement in uncal herniation, which can compress the brainstem and cranial nerves.

Synonyms

  • Uncal gyrus

  • Medial protrusion of the parahippocampal gyrus

Arterial Supply

  • Primarily supplied by branches of the anterior choroidal artery (branch of internal carotid artery)

  • Additional supply from branches of the posterior cerebral artery (especially the uncal branches)

Venous Drainage

  • Drains mainly into the basal vein of Rosenthal

  • Also partially into the inferior cerebral veins and subsequently into the great cerebral vein (vein of Galen)

Function

  • Contains part of the primary olfactory cortex

  • Involved in processing olfactory (smell) information

  • Plays a role in emotional responses and memory due to close anatomical relationships with the amygdala and hippocampus

MRI Appearance

  • T1-weighted images:

    • Uncus appears isointense to the surrounding grey matter

  • T2-weighted images:

    • Uncus is isointense to slightly hyperintense compared to grey matter

  • FLAIR images:

    • Signal is similar to the adjacent cortex; may be slightly hyperintense in some pathological conditions (e.g., edema or gliosis)

CT Appearance

  • Appears as a curved, soft tissue density on the medial aspect of the temporal lobe

  • Difficult to differentiate from adjacent grey matter unless there is a pathological process (e.g., mass effect, hemorrhage)

MRI images

uncus mri 3t coronal image

MRI images

uncus mri 3t sagittal image