Resumen de Tibial marks in bare tibiae: relationship with robusticity indices
A. Trujillo Mederos, Matilde Mercedes Arnay de la Rosa, Carlos Emilio González Reimers, Emilia María Carmona Calero, Juan M. González Toledo, Agustín Castañeyra Ruiz, Alejandra C. Ordóñez, Agustín Lorenzo Castañeyra Perdomo
In bare bones, transverse lines may have several origins. Defleshing of a prey generates cutmarks, which can also appear in relation with traumatic events, post-mortem changes such as marks of animal teeth, rodent gnawing, or impact of stones, or even bone decoration. We hypothesize that in some instances they may be due to hyperplastic vessels beating on the bone surface, as expression of increased blood flow demand imposed by hypertrophied muscles. We analyzed 140 well-preserved tibiae which belonged to pre-Hispanic individuals from El Hierro, in the Canary Archipelago, currently kept at the Department of Archaeology and Prehistory of the University of La Laguna, and determined robusticity indices. Tibial marks were found in 53 out of 140 cases. Epiphyseal and diaphyseal robusticity indices were significantly higher in the first case among those with marks than among those without marks (T=3.13; p=0.002), and nearly significantly in the latter case (T=1.88; p=0.063). Considering only men, similar differences were observed regarding epiphyseal robusticity index (T=2.90; p=0.005) and diaphyseal robusticity index (T=2.11; p=0.039). There were also differences regarding the depth of the tibial marks: a higher epiphyseal robusticity index was associated with a more marked depth of the lines (T=2.11; p=0.042). An association was also observed between depth of the marks and sex (χ2=4.12; p=0.042), more profound marks being observed among men. In conclusion, we here describe subtle bone marks in tibiae, which seem to correspond to vascular imprinting and are related to bone robustness. Whether or not they really represent an adaptation to an increased blood flow demand by hypertrophied muscles in relation with increased weight-bearing activity remains speculative, but this hypothesis may explain their presence.
