part of part of Homo sapiens rib 5 zone of bone organ sternal end of fifth rib 2026-03-19T00:00:00Z A zone of bone organ forming the anterior extremity of the fifth rib that articulates with the costal cartilage of the fifth rib. The costal cartilage of the fifth rib connects to the sternum at the level of the xiphosternal junction, making the fifth rib a true rib. David Osumi-Sutherland