Stafne’s bone defects from Spain: report of four cases and brief archaeological literature review

To present for the first time in the north-western Spanish osteological record prevalence data on Stafne’s bone defect, to compare the results with those reported by other studies, and to increase the dataset for future inter-population comparisons. In all, 143 complete adult mandibles recovered from two necropolises were analyzed (n = 118, San Juan Bautista of Guardo, Palencia province, 16th-19th centuries; n = 25, Plaza del Grano, city of León, 12th-15th centuries). Differential diagnosis of the lesions was made through macroscopic and Computed Tomography (CT) analyses. Four mandibles (n = 3, Guardo, Palencia; n = 1, León) presented bone cavities on the lingual aspect of the mandible below the mylohyoid channel, between the first molar and the angle of the mandible. CT scan showed unilateral well-defined unilocular oval/round concavities in the lingual mandibular cortex below the inferior alveolar canal. Neither the macroscopic nor the radiological characteristics are compatible with inflammatory or malignant pathology, favoring instead a diagnosis of Stafne’s bone defect. Four cases of Stafne’s defects are added to the bioarchaeological inventory. The calculated prevalence is 2.54% for San Juan Bautista and 4% for Plaza del Grano, values in close agreement to those presented in other osteoarchaeological studies. The identification of all examples of Stafne’s bone defects in past populations will contribute to elucidate which factors may be responsible for this trait’s cultural, ecological, temporal, and geographical patterning. The skeletal samples are relatively small. In future investigations of Stafne’s bone defects, CT analysis of dry bone specimens is recommended, whenever possible.