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Topic

design image
Head of hippocampus

The head of the hippocampus is the anterior portion of the hippocampal formation, located in the medial temporal lobe. It lies just posterior to the amygdala, curving into the temporal horn of the lateral ventricle. The head is characterized by multiple digitations (pes hippocampi) that give it a scalloped appearance on coronal sections. It forms part of the limbic system and plays a central role in memory encoding, spatial navigation, and emotional regulation. The hippocampal head is a common site of hippocampal sclerosis, mesial temporal lobe epilepsy, and neurodegenerative changes, making it a critical region in neuroradiology and neurology.

Synonyms

  • Anterior hippocampus

  • Pes hippocampi

  • Hippocampal head

Function

  • Encodes and consolidates short-term memory into long-term memory

  • Involved in spatial learning and navigation

  • Works in coordination with the amygdala for emotional memory processing

  • Acts as a key structure in the limbic circuit for cognitive and behavioral integration

MRI Appearance

T1-weighted images:

  • Hippocampal head shows intermediate gray matter signal intensity

  • Surrounded by hyperintense CSF in the temporal horn and hypointense white matter of the parahippocampal gyrus

  • Digitations of the pes hippocampi may be visualized as scalloped contours on high-resolution images

T2-weighted images:

  • Hippocampal head demonstrates intermediate signal intensity, similar to cortical gray matter

  • CSF in the adjacent temporal horn is hyperintense, outlining its borders

  • Pathology such as hippocampal sclerosis appears as volume loss with increased T2 signal

MRA (Magnetic Resonance Angiography):

  • The hippocampal head itself is not a vascular structure, but adjacent supply from anterior choroidal and posterior cerebral artery branches may be visualized

  • Useful for assessing vascular malformations or ischemia in the mesial temporal region

T1 Post-Contrast (Gadolinium-enhanced MRI):

  • Normal hippocampal head does not enhance

  • Abnormal enhancement may indicate inflammation, neoplasm, or post-ictal changes

  • Critical in differentiating hippocampal sclerosis from tumors or encephalitis

CT Appearance

Non-contrast CT:

  • Hippocampal head appears as isodense to cortical gray matter, limited in detail

  • Atrophy or sclerosis may be inferred indirectly by enlargement of the temporal horn of the lateral ventricle

CT Angiography (CTA):

  • Used to assess vascular supply (via anterior choroidal and posterior cerebral arteries)

  • Helpful in evaluating ischemic injury, AVMs, or hemorrhage affecting hippocampal structures

MRI images

Head of hippocampus MRI IMAGE

MRI image

Head of hippocampus