part of part of Homo sapiens rib 11 zone of bone organ facet of eleventh rib 2026-03-19T00:00:00Z A zone of bone organ on the head of the eleventh rib that forms a single, undivided articular surface for articulation exclusively with the body of the eleventh thoracic vertebra. Because the eleventh rib is an atypical floating rib, its head bears only one facet rather than the two demifacets found on typical ribs. David Osumi-Sutherland