Dorsal root ganglia in the lumbosacral region observed from the axial views of MRI.

A total number of 442 dorsal root ganglia (DRG) in the lumbosacral region of 104 patients were depicted from the axial views of MRI and their localities were classified as intraspinal, intraforaminal, or extraforaminal types. The DRG of the more distal nerve root were located more medially. Asymmetrical locations were observed in 25 pairs of DRG among 221, of which the symptomatic side tended to locate either medially or proximally compared with those on the asymptomatic side.