The objective of this study was to conduct a morphometric analysis of the lumbar nerve roots and surrounding structures. In this investigation, the lumbar roots were studied in 14 cadavers (70 lumbar vertebrae). Lumbar pedicle heights and widths were measured at every level of the lumbar vertebrae. The largest mean root diameter was 5.6 mm (L5 root) and the smallest 3.5 mm (L1 root). With regard to the root-dura exit angle, the widest was measured at L1 as 26.2 +/- 1.6 degrees and the narrowest at L5 as 16.3 +/- 2.4 degrees. The widest lumbar pedicle was measured at L5 as 17.1 +/- 4.2 mm and the narrowest at L1 as 8.4 +/- 1.8 mm. The longest lumbar pedicle was measured at L2 as 15.3 +/- 2.2 mm and the shortest at L4 as 13.8 +/- 2.3 mm. Quantitative measurements of lumbar root diameters, their exit angles from the dura, and lumbar pedicle heights and widths in anatomical dissection models may help us to gain a deeper understanding of the pathologies of this region and positively influence the success of surgical interventions. (c) 2007 Elsevier Ltd. All rights reserved.