part of part of Homo sapiens tetrapod frontal bone zone of bone organ supercilary arch of frontal bone 2026-03-19T00:00:00Z A zone of bone organ forming a curved bony ridge on the external surface of the frontal bone, arching above each orbit immediately superior to the supraorbital margin. It overlies the frontal sinus and is more prominent in males. David Osumi-Sutherland