An Osteological Study of Spina Bifida in the Nariokotome Homo erectus Skeleton

Spina bifida, a type of neural tube defect apparent at birth, has been sporadically documented in paleopathological analyses. It occurs most frequently in the sacrum and has clinical manifestations ranging from mild to severe. However, reporting and interpreting spina bifida from archaeological sacral remains has been difficult because no consensus has been reached about the anatomical indicators of sacral spina bifida. Such a diagnosis is also complicated by the fact that the sacrum is the most variable region of the spine, with many of the morphometric variants being considered normal. This project explored sacral variation in a fossil hominin specimen designated KNM-WT 15000, also known as Nariokotome Boy. This Homo erectus skeleton had been initially suggested to be pathological, due to exhibiting traces of congenital skeletal abnormalities, including spina bifida. However, it has become a subject of controversy, as more recent studies refute this claim. Thus, the objective of the present study was to evaluate these competing claims through the comparative analysis of sacral morphology in KNM-WT 15000 and two prehistoric reference samples from the archaeological sites of Tepe Hissar and Hasanlu in modern-day Iran. The results indicate that the sacrum of KNM-WT 15000 falls within normal morphometric variation compared to the reference samples except in the first sacral vertebra, where an occurrence of spina bifida could be suggested