Cribra orbitalia and porotic hyperostosis: A biological approach to diagnosis.

OBJECTIVES: Porotic lesions of the skull (cribra orbitalia and porotic hyperostosis) are one of the most common types of lesion identified in archaeological human bone and have also been found in hominins and non-human primates. Because of the frequency with which such lesions are found there has been extensive debate on the possible causes and whether they are linked, with much of the debate centering on anemia. The biological approach to diagnosis in paleopathology used by Don Ortner and recently proposed more formally as a technique to facilitate diagnosis in paleopathology by Simon Mays may offer a means of answering some of the questions surrounding these lesions.
MATERIALS AND METHODS: A review was undertaken of biomedical information on changes in the distribution of marrow type and pattern of conversion of red and mixed marrow, and the potential for re-conversion of yellow marrow with age. The range and type of other conditions that might result in the development of porous lesions were also considered.
RESULTS: Combining information from the biomedical literature on marrow type and patterns of conversion with age, with careful evaluation of the type and location of porous lesions in the skull and across the rest of the skeleton will assist in suggesting a diagnosis. DISCUSSION: A wide range of conditions can produce porous lesions in the cranial vault and the orbital roof, but due to anatomical structures and physiological factors such lesions are more likely to occur in the orbital roof. Anemia can produce lesions in both locations, but evidence of marrow expansion is required to confirm it as a cause.