• Hippocampus is a
curved structure on the
medial aspect of
temporal lobe that
bulges into floor of
• Hippocampus – seahorse
• Curved shape which
resembles a shape of a
• Consists of two
interlocking U shaped
gray matter structures
– Hippocampus proper
( Ammon horn)
Superolateral, upsidedown U.
– Dentate gyrus
Head ( Pes hippocampus )
• most anterior part, oriented transversely
• 3 – 4 digitations on superior surface.
• Cylindrical, oriented parasagittally.
• Most posterior, narrows then curves around
splenium to form indusium griseum above cc.
• The hippocampal
sulcus, also known as
fissure, is a sulcus that
separates the dentate
Based of histology
– Cornu Ammonis (CA)
– Dentate Gyrus
• Fascia Dentata
• Hilus (region CA4)
• Medially, the ambient cistern which
separates the hippocampus from
• Choriodal fissure and temporal horn
• Parahippocampal gyrus inferiorly.
• temporal horn of lateral ventricle
amygdala / hippocampal
• The best landmark for separating amygdala
from hippocampus is the anterior temporal
horn, known as the uncal recess.
• The amygdala is always superior to the
• morphology: hippocampal
digitations, (pes hippocampus)
– basilar artery to interpeduncular cistern.
– Morphology: Swiss roll appearance, of two
interlocking U-shaped structures (cornu
ammonis and dentate gyrus)
• The hippocampal body is oval
and found adjacent to the brainstem
• The white matter tracts of the alveus and
fimbria are superior to the hippocampus.
• morphology: smaller and harder to
describe internal structure.
– The hippocampal tail is
demonstrated as it ascends posterior to
– from the point at which the fornix can be
seen in full profile.
Best choice of imaging
• MR in a slightly oblique plane,
perpendicular to long axis of
– Coronal T1 weighted
– Coronal T2 high resolution
– Coronal FLAIR.