Ala; Wing of sacrum - Ala ossis sacri
The ala of sacrum is the upper part of the lateral part of sacrum, lateral to the first sacral vertebra.
It is a large triangular surface, which supports the Psoas major and the lumbosacral trunk, and in the articulated pelvis is continuous with the iliac fossa. It is slightly concave from side to side, convex from before backward, and gives attachment to a few of the fibers of the Iliacus.
Text by Antoine Micheau, MD - Copyright IMAIOS