part of part of Homo sapiens fused sacrum alae of sacrum 2026-03-19T00:00:00Z A skeletal element projection forming the broad, wing-like lateral expansions of the sacral base, lateral to the body of S1, that articulate with the ilium at the sacroiliac joints and support the weight transfer between the vertebral column and the pelvic girdle. skeletal element projection David Osumi-Sutherland