Also called the posterior roots because they are the more posterior of the two nerve fiber bundles (the other being the ventral root), the dorsal roots are formed by afferent axons, whose neurons are contained in the dorsal root ganglia located in the intervertebral foramen. They consist of sensory fibers derived from the skin as well as muscles and tendons. A carrier of somatosensory information to the brain and spinal cord, most of its axons are unmyelinated and distributed to the spinal tray matter on the side of entry. Charles Bell in 1811 and François Magendie in 1822 showed that the dorsal roots of the spinal cord carry sensory input, with motor output being assigned to the ventral roots.
See Dorsal, Dorsal root ganglia (DRG), Dorsal rhizotomy, Gray matter, Myelin, Spinal cord, Ventral roots