Fig. 5From: Identifying the homology of the short human pisiform and its lost ossification centerComparison of pisiform ossification progression in humans, apes, and macaques. Progression of pisiform ossification in humans a, chimpanzees b, gorillas c, orangutans d, and macaques e. Early primary ossifications (Left) and adult morphology (Right) for each species. a Early human pisiform ossification begins at the distal/palmar end (arrow) and does not form a distinct triquetral surface until late in ossification. b–e All non-human primate pisiforms developed a distinct triquetral articular surface during the earliest stages of ossification (arrowhead). Palmar is up and dorsal is down in all panels. Scale bars = 1 cmBack to article page