On porosity of archeological bones I — Textural characterization of pathological Spanish medieval human bones Pedro Bosch a, ⁎, Carlos Moreno-Castilla b , Zulamita Zapata-Benabithe b , Inmaculada Alemán c , Victor Hugo Lara d , Josefina Mansilla e , Carmen Pijoan e , Miguel Botella c a Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México, 0451 México D.F., Mexico b Departamento de Química Inorgánica, Facultad de Ciencias, Universidad de Granada, 18002 Granada, Spain c Laboratorio de Antropología, Facultad de Medicina, Universidad de Granada, 18012 Granada, Spain d Universidad Autónoma Metropolitana — Iztapalapa, Avenida San Rafael Atlixco 186, 09340 México D.F., Mexico e Dirección de Antropología Física, Instituto Nacional de Antropología e Historia, Gandhi s/n, Polanco, 11560 México D.F., Mexico abstract article info Article history: Received 31 March 2014 Accepted 18 September 2014 Available online 2 October 2014 Keywords: Gas adsorption small angle X-ray Scattering Texture Porosity Poblet Granada Bone texture may vary as a function of age, pathology as well as on bone treatments; thus absolute values of specific surface area or porosity are not often reported. A review of the anthropological and archeological refer- ences reveals that the results obtained with the current methodologies for the textural analysis of bone may be contradictory. Indeed, the characterization of archeological bone is a very difficult task through conventional techniques. Still, it is most relevant as porosity is the symptom of several pathologies, for instance anemia, osteoporosis, hyperostosis or syphilis. In this work, archeological bone samples – pathological or healthy – were characterized by nitrogen adsorption– desorption isotherms at -196 °C, small angle X-ray scattering (SAXS) and scanning electron microscopy (SEM). The studied bones are healthy, osteoporotic, hyperostosic, and syphilitic. Porosity, specific surface area, and morphology as well as non conventional features such as roughness, specific surface or fractal dimension, are correlated with the well known macroscopical reported symptoms. The samples come from Moorish Andalucía (Grenade) and Medieval Catalonia (Poblet Monastery). © 2014 Elsevier B.V. All rights reserved. 1. Introduction Bone is constituted by connective tissue composed of an organic protein, collagen, and a mineral component, hydroxyapatite (Weiner and Traub, 1992; Labastida Pólito et al., 2006). Collagen appears in bone as beams of white inelastic fibers with an enormous tensile strength. Those fibers include fibrils, which are formed by smaller filaments: the collagen protein that is the most abundant protein in animal tissues. Human collagen protein contains a high percentage (23 to 30%) of proline and hydroxyproline amino acids. The end space of the collagen fibrils is the nucleation center for calcium phosphate, i.e., hydroxyapatite. Depending on collagen fiber orientation, two types of bone are distinguished: cortical which appears in long bones or trabecular that may be found in vertebrae or extremities of long bones. Note that lamellar bone is not restricted to cortical, but refers to the organization of the collagen fibers. Normal adult human trabecu- lar bone is lamellar as well. Human bones have three main cavities: Harvesian canals (50 μm), osteocytic voids (quasi ellipsoidal and a few μm in size) and canaliculi (found between the lacunae, their diameter is less than one μm). Still, there are other cavities in bone besides these, e.g. , the canals of forming osteons, and resorptive bays which are much larger, and vascular canals. The cortical porosity increases from approximately 8% for young indi- viduals up to 24–28% for elderly individuals. Harvesian canals increase significantly with age whereas lacuna porosity decreases slightly (Martin, 1984; Wang and Ni, 2003). There are pathologies such as anemia (Domínguez-Rodrigo et al., 2012), syphilis (Lopes et al., 2010), leprosy (Roffey and Tucker, 2012), or co-deficiency of vitamin C and B 12 (Walker et al., 2009) well known for their impact on bone porosity. Furthermore, bone pores may be modified, also, by postmortem thermal treatments (Bosch et al., 2011). In this work, we have chosen to study and compare bones which at first glance, i.e. by macroscopical criteria, are altered in their porosity at various degrees (Ortner, 2011). They correspond to Moorish Andalucía and Medieval Catalonia, in Spain. As bone evolves with age and pathol- ogy as well as with bone treatments, the characterization of bone texture is hard work, and no absolute values of specific surface area or porosity are acceptable. A review of the anthropological and archeological references reveals that the results obtained with the current methodologies for the textural analysis of bone are often contradictory. It is difficult to understand Palaeogeography, Palaeoclimatology, Palaeoecology 414 (2014) 486–492 ⁎ Corresponding author. Tel.: +52 56 22 46 56. E-mail address: croqcroq@hotmail.com (P. Bosch). http://dx.doi.org/10.1016/j.palaeo.2014.09.018 0031-0182/© 2014 Elsevier B.V. All rights reserved. Contents lists available at ScienceDirect Palaeogeography, Palaeoclimatology, Palaeoecology journal homepage: www.elsevier.com/locate/palaeo