part of part of Homo sapiens fused sacrum zone of bone organ linea terminalis of sacrum 2026-03-19T00:00:00Z A zone of bone organ forming the sacral contribution to the linea terminalis, constituting the posterior arc of the pelvic brim and demarcating the boundary between the greater and lesser pelvis at the level of the sacral promontory and alae. David Osumi-Sutherland