Bifid ribs in ancient human populations: a systematic reassessment

Bifi d ribs (also known as “bifurcated ribs”) are a rare congenital anomaly that accounts for ca. 28% of described rib abnormalities. Th eir presence in modern populations has been reported in both anatomical and radiological studies, but this anomaly’s antiquity has never been subjected to a systematic assessment, it oft en being merely mentioned anecdotally. Th e present study consists of two parts: a. a morphological and radiological examination of cases from 3 diff erent sites, each one distant no more than 1.5 km from one another and all of them located around the city of Brześć Kujawski, north-central Poland, in the historical land of Kujawy. Th e three populations date back to the Neolithic (4600-4000 BCE), the Middle Ages (12th-16th centuries CE), the Modern Era (15th-19th centuries CE). All analyzed skeletal series came from the collections of the Department of Anthropology, University of Łódź and the Museum of Archaeology and Ethnography in Łódź. Th e possession and the analysis of the samples were in accordance with the legal status of archeological human remains in Poland. b. a comprehensive reassessment of the published literature based not only on traditional biomedical databases (Scopus, Web of Science, Pubmed, etc.) but also archeological monographs and posters. Th e frequency of bifi d rib in the studied populations is 0.4% (3/752 individuals). Th e lesions were found in typical ribs: the fourth left rib of a male from the Neolithic population, the fifth right rib of an individual of unknown sex from the medieval population and two right ribs (the third and the fourth) of a male from the Early Modern series. Th eir appearance differs from a barely visible dichotomy with poorly marked independent surfaces on sternal end of rib, to a clear division (approx. 3 cm) with asymmetry in the size of each bifurcated part. Finally, the presentation offers a comprehensive geographical distribution of this anomaly and practical suggestions on how to avoid misinterpreting it in the anthropological record.