Brain, fornix of the

An arching fibrous band in the brain connecting the two lobes of the cerebrum. (The cerebrum is the largest part of the brain and consists of two hemispheres separated by a deep longitudinal fissure). Each fornix — there are two — in the brain is an arched tract of nerves. In anatomy, a fornix is a vaultlike or arched structure. "Fornix" is the Latin word for "vault or arch." One can find a fornix in numerous areas of the body. The fornix of the conjunctivae refers to loose arching folds connecting the conjunctival membrane lining the inside of the eyelid with the conjunctival membrane covering the eyeball. The fornix of the vagina refers to the anterior (front) and posterior (back) recesses into which the upper vagina is divided. These vaultlike recesses are formed by protrusion of the cervix into the vagina. ("Fornix" is closely related to "fornication." It seems that prostitutes in ancient Rome used to hang out under the arches of certain public buildings. The act of carrying on an illicit sexual relationship consequently came to be called "going under the arches": fornication.)