Morphometric Analysis of Lumbar Intervertebral Foramen: A Radiographic Study

Objective. To investigate the anatomic relation among the dimensions of the lumbar intervertebral foramen (LIVF) and the intervertebral disc (IVD) in the normal spines. Summary of Background Data. Although many anatomic studies have been done to investigate the relationships between the foraminal dimensions and degenerative lumbar diseases, the anatomic relation among the dimensions of the intervertebral foramen and the IVD in the normal lumbar spine have not been fully elucidated. Methods. 80 healthy volunteers (42 male and 38 female; age, 18-58 years) were classified into four age groups. Lateral plain radiographs of their lumbar spines were taken. The disc height (DH), vertebral body height (VH), foraminal height (FH), foraminal width (FW), height of superior articular process (HSAP) and foraminal area (FA) were measured on the plain radiographs based on a "guide line." The anatomic relation among the dimensions of the LIVF and IVD were analyzed. Results. The gender factor has shown a significant difference with the DH and VH, but no significant difference with the dimensions of LIVF. Positive correlations were demonstrated between the FA and the VH (R = 0.383, P < 0.001), the FH (R = 0.662, P < 0.001), the FW (R = 0.761, P < 0.001) and the HSAP (R = 0.728, P < 0.001). However, the statistical analysis showing there was no correlation between the DH and the FA (R = 0.081, P = 0.105) in the normal lumbar spine. Conclusion. In the normal lumbar spine, the conditions of the intervertebral foramen have a significant correlation with the dimensions of the bony structure which forming its boundaries, but no correlation with the IVD.