part of part of Homo sapiens rib 1 non-articular facet of tubercle of first rib 2026-03-19T00:00:00Z A skeletal element projection constituting the roughened, non-articular region of the tubercle of the first rib that provides attachment for the costotransverse ligament. In the first rib the tubercle is prominent on the superior surface, and its non-articular facet is directed posteriorly toward the transverse process of the first thoracic vertebra. skeletal element projection David Osumi-Sutherland