Velum interpositum
Updates to Article Attributes
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 matter forming a triangular membrane the apex of which points anteriorly.
Boundaries
- superiorly
- the: the columns of the fornices and hippocampal commisure (psalterium) reaching as far forward as the foramen of Monro. - inferiorly
-: the internal cerebral veins and tela choroidea of the third ventricle - inferolaterally
- the: the thalamus. - posteriorly
- the: the narrow base of the triangle abuts the splenium of the corpus callosum 1
It varies in shape from persion 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 2.
-<p>The <strong>velum interpositum</strong> is a small membrane containing a potential space just above and anterior to the pineal gland which can become enlarged to form a <a href="/articles/cavum-velum-interpositum">cavum velum interpositum</a>. </p><h4>Gross anatomy</h4><p>The velum interpositum is formed by an invagination of <a title="Pia mater" href="/articles/pia-mater">pia matter</a> forming a triangular membrane the apex of which points anteriorly.</p><h5>Boundaries</h5><ul>-<li>superiorly - the columns of the <a href="/articles/fornix">fornices </a>and <a href="/articles/hippocampal-commisure">hippocampal commisure</a> (psalterium) reaching as far forward as the <a href="/articles/interventricular-foramen-of-monro-1">foramen of Monro</a>.</li>-<li>inferiorly - the <a href="/articles/internal-cerebral-vein">internal cerebral veins</a> and <a href="/articles/tela-choroidea">tela choroidea</a> of the <a href="/articles/third-ventricle">third ventricle</a>- +<p>The <strong>velum interpositum</strong> is a small membrane containing a potential space just above and anterior to the pineal gland which can become enlarged to form a <a href="/articles/cavum-velum-interpositum">cavum velum interpositum</a>. </p><h4>Gross anatomy</h4><p>The velum interpositum is formed by an invagination of <a href="/articles/pia-mater">pia matter</a> forming a triangular membrane the apex of which points anteriorly.</p><h5>Boundaries</h5><ul>
- +<li>superiorly: the columns of the <a href="/articles/fornix">fornices </a>and <a href="/articles/hippocampal-commisure">hippocampal commisure</a> (psalterium) reaching as far forward as the <a href="/articles/interventricular-foramen-of-monro-1">foramen of Monro</a>
-<li>inferolaterally - the <a href="/articles/thalamus">thalamus</a>.</li>-<li>posteriorly- the narrow base of the triangle abuts the splenium of the <a href="/articles/corpus-callosum">corpus callosum</a> <sup>1</sup>- +<li>inferiorly: the <a href="/articles/internal-cerebral-vein">internal cerebral veins</a> and <a href="/articles/tela-choroidea">tela choroidea</a> of the <a href="/articles/third-ventricle">third ventricle</a>
- +</li>
- +<li>inferolaterally: the <a href="/articles/thalamus">thalamus</a>
- +</li>
- +<li>posteriorly: the narrow base of the triangle abuts the splenium of the <a href="/articles/corpus-callosum">corpus callosum</a> <sup>1</sup>