Studies on the human aortic bifurcation. Part 2. Predilection sites of early lipid deposits in relation to preformed arterial structures.

The site of fatty streaking in the human aortic bifurcation has been re-examined in 22 specimens from persons who died suddenly between the ages of 14 and 35 years. In contrast to the earlier data of others which pointed to the predominant involvement of either lateral or medical wall, fatty streaking has been found to be localized initially along the posterior wall of the bifurcation and its daughter vessels, i.e. common iliac arteries. This localization appears to be related to a prominent development of the intima along the posterior wall of the bifurcation. The appearance of fatty streaking along this wall may also be favored by the slightly curved pattern of the human aortic bifurcation. The morphometric analysis demonstrates a greater involvement of right common iliac artery by fatty streaking as compared with the left artery. The elastic sheet covering the divider of the bifurcation was identified microscopically as another common site of an early lipid deposition in the aortic bifurcation. The early lipid infiltration of the elastic sheets is partly responsible for the diffuse reddish coloration ("blush") appearing with gross fat staining at the lateral aspects of the divider and in other affected areas.