Morphometric Analysis of the L4–L5 Lumbar Intervertebral Foramen in Adults: A Computed Tomography-based Observational Study

Introduction:The lumbar intervertebral foramen (IVF) serves as a passage for spinal nerves and vessels, and its dimensions may vary with age and sex.Morphometric data derived from imaging can enhance understanding of foraminal anatomy and its clinical implications.The present study aimed to analyze the morphometry of the L4-L5 IVF using computed tomography (CT) and to evaluate age-and sex-related differences in selected parameters.Materials and methods: This observational, cross-sectional study included 51 asymptomatic adult CT scans (25 males, 26 females; mean age 35.82 12.61 years) obtained in the supine position.Sagittal images at the exit slice of the L4-L5 IVF were analyzed using RadiAnt DICOM Viewer.Four parameters were measured: Disc height (DH), pedicle to superior articular process distance (P-SAP), posteroinferior margin of the upper vertebra to superior articular process distance (IPV-SAP), and pedicle to inferior vertebra distance (P-IV).Data were analyzed using SPSS v22.Statistical tests included t-test, Wilcoxon-Mann-Whitney U-test, and Spearman correlation, with significance set at p < 0.05.Results: Males showed greater DH and P-SAP values bilaterally compared with females, whereas IPV-SAP and P-IV values exhibited minor sex differences.The IPV-SAP distance at the exit slice was significantly higher in individuals aged >40 years, suggesting age-related morphological widening of the foramen.Other parameters showed nonsignificant but similar trends. Conclusion:The exit zone of the L4-L5 IVF exhibits subtle age-related dimensional changes, particularly in the IPV-SAP distance, which may reflect adaptive or degenerative alterations.These morphometric findings provide valuable baseline data for anatomical and radiological reference and may aid in the interpretation of age-related lumbar foraminal narrowing.