The studies of 16th century colonial period osleological remains from the ingenous community of Los Olmos (Tizayuca, Hidalgo State) disclose the repeated presence of an annex articulate mask in the first metatarsal, exclusive to the female sex. Therefore, we suppose that its formation is because of a posture costum arily related to some female activities. As evidenced in several codexes, women were in the habit of kneeling down flexed with toes in flexion; that position might have created the articulate mask while they were grinding on a flat stone, weaving or spinning. The last activity coincides with the abundant presence of spindle whorls found in archaeological excavation.Esta investigación tiene como objetivo averiguar cual es el origen de la presencia reiterada de una carilla articular accesoria del primer metatarsiano, dicha característica tiene una presencia exclusiva del sexo femenino. Los resultados muestran que esta característica se debe a una postura hincada de rodillas con los pies hiperflexionados, postura adoptada para moler e hilar, los resultados obtenidos en esta investigación fueron cotejados con información arqueológica y etnohistórica.