What Is the Septum Pellucidum?

Septo-optic dysplasia causes the underdevelopment of the optic nerve, the nerve which transmits the signals of the eye to the brain.
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  • Written By: Alex Said
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  • Last Modified Date: 14 February 2015
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The septum pellucidum is a thin, triangular membrane that separates the brain's lateral ventricles. This membrane forms a barrier between these parts of the brain, but is not thought to have any particular function itself. It extends from the the corpus collosum, a collection of neural fibers under the cortex, to the fornix, a group of fibers above the thalmus. The absence of the septum pellucidum has been connected to some medical conditions, such as septo-optic dysplasia.

This membrane is located in the center of the brain near the midline, between the right and left hemispheres. It is surrounded on three sides — above, below, and in front — and is connected to the corpus collosum, the neural fibers that connect the cerebral hemispheres. On either side are the lateral ventricles, which are filled with cerebrospinal fluid. In back, the septum pellucidum is connected to the fornix, fibers that carry signals from the hippocampus.

The membrane is composed of two layers, called laminae septi pellucidi, each of which is made up of both gray and white matter. Before birth, there are cavities or divisions between the layers of the septum pellucidum. The layers usually fuse within the first six months after birth, but in about 10% of people, it never does. Although most people with this condition do not appear to have any symptoms, it has been loosely connected to mental disturbances and problems with speech.


If the septum pellucidum does not form, such as due to a genetic mutation, it can cause more serious neurological problems. It is a major sign of a condition called septo-optic dysplasia, in which the patient also has an underdeveloped optic nerve and often some amount of pituitary deficiency. Other problems can include seizures, problems with coordination, and dysfunction of the hypothalmus.

There are several variations in the formation of the septum pellucidum. A cavum vergae, for example, is a separation in the layers of the membrane in the rear of the membane, usually extending to the to the splenium of the corpus callosum. The splenium is the rear-most portion of the corpus callosum. The cavum septum pellucidum is a space near the front of the membrane. In most cases, these variations are not symptomatic, and cause the person who has them no difficulties.



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Post 3
But I believe that Hippocrates was of Greek origin, no? As was Plato. I believe there is more to it than just them.
Post 2
I think it might have a lot to do with the fact that a lot of our medical knowledge comes from the ancient scholars and thinkers of that time. People like Hippocrates, Plato, Thermophiles and others had a hand in naming and defining quite a few things.
Post 1
I have always wondered why a lot of the names for body parts for humans are in Latin. And it seems especially true for the human brain. A lot of words listed here end with what sounds like Latin. The exceptions are the organs and parts that have meanings and names rooted in other words.

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