part of part of Homo sapiens sternum zone of bone organ transverse ridges of sternum 2026-03-19T00:00:00Z A zone of bone organ comprising the low, horizontal bony ridges on the anterior surface of the sternal body that mark the lines of fusion between adjacent sternebrae during development, typically three ridges dividing the body into four segments and remaining palpable on the adult sternum. David Osumi-Sutherland