Commissures of the brain

Commissure refers to a bundle of nerve fibers that cross the midline at their level of origin or entry (as opposed to a decussation of fibers that cross obliquely).

The most common usage of the term refers to the brain's commissures, of which there are five—the anterior commissure, posterior commissure, corpus callosum, hippocampal commissure (commissure of fornix), and habenular commissure—and which consist of fibre tracts that connect the two cerebral hemispheres and span the longitudinal fissure. In the spinal cord is found the anterior white commissure.