velum interpositum
The velum interpositum is a small membrane containing a potential space just above and anterior to the pineal gland which can become enlarged to form a cavum velum interpositum.
Gross anatomy
The velum interpositum is formed by an invagination of pia mater forming a triangular membrane the apex of which points anteriorly.
Boundaries
- superiorly: the body of the fornix and hippocampal commissure (psalterium) reaching as far forward as the foramen of Monro
- inferiorly: the internal cerebral veins and tela choroidea of the third ventricle
- inferolaterally: the thalamus
- posteriorly: the narrow base of the triangle abuts the splenium of the corpus callosum
It varies in shape from person to person, sometimes interposed between the internal cerebral veins and splenium, and depending on whether or not there is a cavum vergae (in which case the columns of the fornices are displaced inferiorly, narrowing the velum interpositum).
When somewhat distended by fluid it forms a small triangular (in axial section) space and is referred to as a cavum velum interpositum. If larger and exterting mass effect it is known as a cavum velum interpositum cyst.
The space between the two leaves of pia contains the posterior medial choroidal arteries .
Siehe auch:
- Thalamus
- Corpus callosum
- Cavum septi pellucidi et vergae
- dritter Ventrikel
- internal cerebral veins
- Cavum veli interpositi Zyste
- Foramen interventriculare Monroi
und weiter:
Assoziationen und Differentialdiagnosen zu velum interpositum:
