The columns of fornix are known as anterior pillars and fornicolumns. These exist within the brain.

Fornix is Latin for 'vault' and 'arch', representing the shape of the columns of fornix. The columns begin on either side of the brain, and separately are known as the crus of the fornix. When the fibers come together to form the fornix, it is called the body of the fornix. In the brain, the columns of fornix travel downward in an arch, falling in front of the interventricular foramen (an opening at the center of the brain) and going behind the anterior commissure (a bundle of fibers that connects the brain’s halves).

From there, the columns of fornix travel the lateral wall of the third ventricle — a fluid-filled cavity in the brain — passing through gray matter, a type of tissue found in the outer portions of the brain. This continues to the base of the brain, where the columns end at the corpus mammillare, or mammillary bodies, which help with recall and the role of smell in memory.

The columns of fornix are C-shaped. The columns are created from columns of fibers called axons. These axons are found in the brain and can carry signals throughout. Signals created by the hippocampus (part of the brain involved in memory) are sent to the septal nuclei (involved in pleasure and memory formation) by the fornix, as well as to the mammillary bodies.