Septum pellucidum

The septum pellucidum is a thin transparent membrane located in the brain between the body and anterior horns of the lateral ventricles.

Gross anatomy

It extends from the rostrum, genu and anterior portion of the body of the corpus callosum to the fornix. It separates the anterior horns of the lateral ventricles and has two layers (laminae) that are adherent to each other. The function of the septum pellucidum is not fully understood . The septum pellucidum is 1.5-3.0 mm thick.


  • superior: body of corpus callosum
  • inferior: rostrum of corpus callosum
  • anterior: genu of corpus callosum
  • posterior: third ventricle
  • lateral: anterior horns and body of lateral ventricles


The septum pellucidum is lined with ependymal cells on its ventricular side whilst pia mater lines the cavity. It also contains scattered glial cells, nerve fibers and veins .

Variant anatomy


The septum pellucidum develops at 10-12 weeks of gestation from the primitive lamina terminalis or the commissural plate. Its development is closely linked with that of the corpus callosum and is complete by 17 weeks of gestation .

History and etymology

Derived from the Latin word "pellucidum" meaning transparent.