Topics

Topic

design image
Tail of hippocampus

The tail of the hippocampus is the posterior portion of the hippocampal formation, continuous with the body of the hippocampus and curving upward into the atrium and posterior horn of the lateral ventricle. It forms part of the floor of the inferior horn of the lateral ventricle and extends posteriorly toward the splenium of the corpus callosum. The tail is closely related to the fimbria of the hippocampus, which continues into the fornix.

Histologically, the hippocampal tail contains the same layered architecture as the rest of the hippocampus—CA fields (cornu ammonis), dentate gyrus, and subiculum. Though smaller in size compared to the head and body, it contributes to memory consolidation, visuospatial navigation, and integration of sensory input.

Synonyms

  • Hippocampal tail

  • Posterior hippocampus

  • Caudal hippocampus

Function

  • Contributes to episodic memory consolidation and retrieval

  • Plays a role in spatial orientation and navigation

  • Connects with parahippocampal and posterior cortical areas, integrating sensory and spatial information

  • Involved in limbic system pathways via the fimbria and fornix

MRI Appearance

T1-weighted images:

  • The tail of the hippocampus appears as a curved, intermediate signal intensity structure forming part of the floor of the atrium/posterior horn of the lateral ventricle

  • Clearly outlined by CSF (hypointense on T1) in the ventricle

  • Pathology (atrophy, sclerosis, tumors) shows volume loss, signal alteration, or abnormal enhancement

T2-weighted images:

  • Appears as a curved, intermediate to slightly hyperintense structure, relative to surrounding white matter

  • Surrounded by hyperintense ventricular CSF, providing good contrast

  • Atrophy, edema, or gliosis appear as increased signal intensity and reduced bulk

MRA (Magnetic Resonance Angiography):

  • Not primarily used for hippocampal imaging, but adjacent vessels (posterior cerebral artery branches, hippocampal arteries) may be evaluated for vascular supply

  • Useful in epilepsy evaluation or ischemic changes in hippocampal territory

T1 Post-Contrast (Gadolinium-enhanced MRI):

  • Normal hippocampal tail shows no significant enhancement

  • Pathological processes (e.g., hippocampal tumors, inflammatory disease, or encephalitis) demonstrate abnormal enhancement

CT Appearance

  • The hippocampal tail is seen as a soft tissue density structure forming part of the floor of the posterior horn of the lateral ventricle

  • Contrast with surrounding hypodense CSF helps outline it

  • CT is less sensitive than MRI but useful for detecting calcification, hemorrhage, or large destructive lesions

  • Atrophy may appear as ventricular enlargement with volume loss of the hippocampal tail

MRI images

Tail of hippocampus MRI SAG IMAGE