Choroidal fissure

Last revised by Zdenko Kasáč on 15 Feb 2024

The choroidal fissure, or choroid fissure, is a cleft of the medial surface of the cerebral hemisphere running immediately above the hippocampus and extends around the thalamus to the interventricular foramen of Monroe. It forms the medial wall of the lateral ventricle and attachment site for the choroid plexus.

Gross anatomy

The choroidal fissue is a C-shaped fissure in the medial wall of the cerebral hemisphere; extending from the interventricular foramen of Monroe, to around the thalamus and cerebral peduncle as far as the uncus of the temporal lobe.

The convexity of the C shape is contained by the body and crus (pillar) of the fornix, the fimbria and the hippocampus.

The concavity of the C shaped slit is contained by the thalamus (upper and posterior surfaces) and the tail of the caudate nucleus.

The slit of the choroid fissure is where pia mater and ependyma are in direct contact with each other; evaginating into the lateral ventricles as choroid plexus1.

Opening the choroidal fissue between the fornix and the thalamus will lead into the velum interpositum.

At the level of the hippocampus, the choroidal fissure is a lateral extension of the transverse fissure of Bichat, which in turn is a lateral extension of the ambient cistern 4,5

The choroid plexus originates at the inferior choroidal point of the choroidal fissure, which is located just posterior to the hippocampal head. At this location, the anterior choroidal artery enters the temporal horn of the lateral ventricle. Only choroid plexus and a thin arachnoid membrane separate the cerebrospinal fluid space of the choroidal fissure and the lateral ventricle.

Related pathology

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Cases and figures

  • Figure 1: choroidal fissure
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