Anatomical Variations of the Position of the Aortic Bifurcation, Iliocava Junction and Iliac Veins in Relation to the Lumbar Vertebra
Kajorn Lakchayapakorn MD*, Yongyut Siriprakarn MD**
Affiliation : * Division of Anatomy, Department of Preclinical Science, Thammasat University, Bangkok ** Department of Orthopedic Surgery, Thammasat University, Bangkok
Objective : To determine the position of the aortic bifurcation and the iliocava junction in relation to the
lumbar vertebra, aortic bifurcation angle, interiliac angle, and anatomical variation of the iliac veins anterior
to the lumbar vertebra of Thai people.
Material and Method: The present study was done on 65 cadavers. The mean ages of the cadavers were 73 +
10 years (range from 50 to 90 years). The dissections were performed by anterior approach to the lumbar
vertebra. The position of the aortic bifurcation and the iliocava junction, aortic bifurcation angle and interiliac
angle were measured in relation to the lumbar vertebra. Anatomical variations of the iliac veins were observed
anterior to the lumbar vertebra.
Results : The aortic bifurcation was between L3 and L5, most often at the L4 vertebral body level (63%), at the
middle third in vertical plane of vertebra (31%) and at the median third in horizontal plane of vertebra (57%).
The iliocava junction was between L4 and L5-S1 disc, most often at the L5 vertebral body level (69%), at the
upper third of vertebra (28%) and at the right lateral third in horizontal plane of vertebra (60%). The mean
aortic bifurcation angle was 54° (male 55°, female 53°). No significant difference in the mean aortic bifurcation
angle was observed between male and female at p > 0.05 and the mean interiliac angle was 71° (male 73°,
female 68°). A significant difference in the mean interiliac angle was observed between male and female at
p < 0.05. In the abdomen, variation of common iliac vein was found on the left side connecting IVC with left
external iliac vein.
Conclusion : The anatomical variations of the position of the aortic bifurcation, iliocava junction, and common
iliac veins at the anterior of lumbar vertebra can be found in a normal population and cause trouble to
vertebral surgery during the operation. Therefore, precaution and full investigation of the anatomical position
of the vessels might be required before surgery is performed.
Keywords : Aortic bifurcation, Iliocava junction, Lumbar vertebra, Iliac vein, Anatomical variation
