Morphometry of the Iliolumbar Artery and the Iliolumbar Veins and Their Correlations with the Lumbosacral Trunk and the Obturator Nerve

Abstract

ABSTRACT Objectives: To reveal the variations of the iliolumbar artery and the iliolumabar veins and their correlation with the surrounding important structures. Methods: We dissected the iliolumbar region bilaterally in 20 formalin-fixed adult cadavers. The diameter of the iliolumbar artery at its origin, its length up to the branching point, the distance between the iliolumbar artery and the inferior margin of the fifth lumbar vertebra and the distance between the iliolumbar artery and the bifurcation point of the common iliac artery, were measured. The pattern of drainage, the dimensions, the points of confluence with the common iliac vein and the obliquity of the iliolumbar vein were noted. The correlation between the iliolumbar artery and the veins to the obturator nerve and the lumbosacral trunk was recorded. Results: The iliolumbar artery originated from the posterior trunk of the internal iliac artery or from the internal iliac artery. The mean diameter of the iliolumbar artery, at its origin, was 3.5±0.5 mm. The mean distance between the origin of the iliolumbar artery and the bifurcation point to the iliac and the lumbar branches was 12.2±5.5 mm. The distance between the origin of the iliolumbar artery and the lower edge of the fifth lumbar vertebra was 43.2±11.6 mm. The distance between the origin of the iliolumbar artery and the bifurcation point of the common iliac artery was 38.7±10.6 mm. The mean distance of the iliolumbar veins from the inferior vena cava, overall, was 35± 9.9 mm. The mean width of the mouth of the iliolumbar vein was10.7 ± 5.1 mm and the mean angle of obliquity of the vein with respect to the long axis of the common iliac vein was 75.50 . The tributaries which drained into the main iliolumbar vein were variable. The iliolumbar artery passed anterior in 70% and it passed posterior to the obturator nerve in 30%. The veins were lying anterior to the obturator nerve in 45% and they were lying posterior in 55%. The multiple tributaries which drained into the iliolumbar vein relation of the tributaries were variable, few passed anterior and few passed posterior. The iliolumbar artery was seen anterior to the lumbosacral trunk in 30%, it was posterior in 54%, it was cleaved in 8% and the branches of the artery were passing on either side of the lumbosacral trunk to enclose it like a clasp in 8%. The veins were anterior to the lumbosacral trunk in 40% and they were posterior in 60%. Conclusion: The anatomical features of the iliolumbar artery, the iliolumbar veins and their correlation with the anatomical landmarks, which were presented here, would be helpful in decreasing the iatrogenic trauma to the neurovascular structures in the iliolumbar region.

Keywords

• iliolumbar artery
• iliolumbar veins
• obturator nerve
• lumbosacral trunk
• injury
• spine surgery