A rare naviculocuneiform I coalition from Bronze Age Siberia

Naviculocuneiform coalitions are among the least common types of tarsal coalition, a rare congenital anomaly characterized by incompletely separated tarsal bones. Only a handful of cases have been documented from the archaeological record, none of which have been recovered from north central Asia or date to earlier than about 2000 years B.P. Here, we present a case of nearly complete osseous coalition of the left navicular and cuneiform I from the early Bronze Age (ca. 5200/5000–4000 cal. BP) Lake Baikal region of Siberia (Russian Federation). We also provide substantial evidence for the congenital (rather than acquired) basis of this unusual condition and discuss, using modern clinical data, possible intra vitam complications.

► Osseous naviculocuneiform coalitions are rare congenital defects of the foot.
► This 4000-year-old case from Siberia is the nearly complete union of two tarsals.
► A differential diagnosis strongly supports the congenital nature of the coalition.
► Micro-CT imaging reveals continuous trabecular architecture between the two bones.
► This is perhaps the oldest naviculocuneiform coalition reported in the literature.