An anatomic study of foraminal nerve root lesions in the lumbar spine.

An anatomic study of lumbar nerve root lesions in the foraminal zone was performed on 35 cadavers. Two morphologic abnormalities of the nerve roots in the intervertebral foramen were found. The first was an abnormal transverse course of the nerve roots. The second was an indentation on the dorsal root ganglia caused by compression of the superior articular facet, degenerative bulging discs, or both. The incidence of indentation on the dorsal root ganglia was dependent on location of the ganglia or age. For details, at the L5 root level, the ganglia located in the proximal part of neuroforamen had the highest incidence, and extraforaminally located ganglia have the lowest incidence of indentation. The incidence of indented dorsal root ganglia increased with age. The possible correlation between these observed anatomic abnormalities and clinical symptoms must be further elucidate.