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Hippocampal head

The hippocampal head is the anterior and enlarged part of the hippocampus, a key structure located in the medial temporal lobe of the brain. Functionally crucial for memory encoding and spatial navigation, the hippocampal head forms the anterior segment of the hippocampal formation and lies adjacent to the amygdala and the uncal region. Its distinct anatomical, vascular, and radiological features make it a critical focus in neuroimaging and clinical neurology.

Synonyms

  • Pes hippocampi

  • Anterior hippocampus

  • Hippocampal anterior segment

Arterial Supply

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

  • Additional small branches from the posterior cerebral artery (PCA), mainly via the anterior hippocampal branches.

  • Some supply from the uncal branch of the PCA.

Venous Drainage

  • Drained mainly by the hippocampal veins, which empty into the basal vein of Rosenthal.

  • The basal vein subsequently drains into the great cerebral vein (vein of Galen).

  • Additional minor drainage into the inferior ventricular vein.

Function

  • Essential role in memory formation and consolidation (especially episodic and spatial memory).

  • Involved in learning and navigation.

  • Associated with emotional regulation due to proximity to the amygdala.

  • Clinical relevance: susceptible to hypoxic damage, epilepsy, Alzheimer’s disease, and other neurodegenerative conditions.

MRI Appearance

  • T2-weighted imaging:

    • Hippocampal head shows intermediate to slightly hyperintense signal compared to adjacent white matter; prominent internal architecture with visible digitations (“pes” pattern).

  • T1-weighted imaging:

    • Isointense to slightly hypointense relative to cerebral cortex; digitations less obvious than on T2.

  • FLAIR imaging:

    • Similar to T2, but suppression of CSF in the adjacent temporal horn; internal structure preserved unless pathology is present (e.g., sclerosis, edema).

CT Appearance

  • Non-contrast CT:

    • The hippocampal head is difficult to delineate specifically; appears as a gray matter structure in the anterior medial temporal lobe.

    • Hypodense changes may be seen in cases of acute infarction or edema.

    • Calcification is not typical in the normal hippocampal head.

MRI images

Hippocampal head mri 3t coronal image

MRI images

Hippocampal head mri 3t sagittal image