The tapetum was described by Reil (1759-1813), who also described the insula. The name means carpet or tapestry, and was applied to the fibers of the corpus callosum that pass over the lateral ventricle. In addition to the major and minor forceps, and the fibers that cross the corona radiata, there are other fibers from the splenium that go to form the lateral wall of the temporal horn and the lateral wall and roof of the occipital horn.

      The fibers of the tapetum connect the inferior temporal lobes on both sides, as part of the corpus callosal function. The tapetum is supplied by the long penetrating branches of the middle cerebral artery and also by the branches of the posterior cerebral artery around the trigone.

      On MRI, the tapetum appears hypointense on T2W images, due to the high axonal density, and the adjacent optic radiations appear hyperintense due to the less axonal density.

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