Osseous Microanatomy and Histochemical Characterization in Species, Gender Determination and Age Estimation

Abstract

Background: Bone is a tissue of particular interest, because the hard tissue of the skeleton is normally well preserved and details of microscopic structure can be seen in specimens many centuries old. The microscopic structure of bone can be utilized for identification of unknown bone samples in forensic odontology. Physical anthropologists may encounter complete or fragmentary specimens of bone in which standard anthropometric methods provide inconclusive or questionable information. If the histological structure of such material could reveal, with reasonable accuracy, details of species, age, and gender, it would be a useful and valuable laboratory tool. Materials and Methods: A cross-sectional analysis of formalin fixed paraffin embedded sections from biopsied lesions (5 cases each of goat bone, 5 cases of chicken bone specimen, 5 cases of human male bone specimen, 5 cases of human female bone specimen) was done. The variation of the trabeculae by measuring the average width of trabeculae, the average marrow space, and the ratio of the above two through morphometric analysis was assessed. The observational percentage variation amongst the species by number of osteons, osteocytes shape i.e., -spindle, elliptical and round, presence of inflammation was noted. The stroma and hard tissue for Collagen characterization (Special stains)Type, orientation and maturity using Picrosirus stain, Sub intimal fibrosis surrounding the bone using Van Gieson, Percentage of mature and immature bone pattern using Azan stain was analyzed. Result: Chicken bone shows absence of osteons in comparison to human bone with increased number of osteocytes. Goat bone shows plexiform pattern with scattered haversian canals more comparable to human bone architecture. Average human Haversian canal diameter was greater than non-human mammalian species. Azan staining helped in differentiation of mature from immature bone. Picrosirus staining helped in establishing collagen type, orientation and thickness. Sub intimal fibrosis surrounding the bone was checked using Van Gieson staining. Discussion: The complexities of bone tissue and its growth processes are such that misinterpretations of a critical nature can be made if the observer is not well informed on the multitude of basic details dealing with Osteogenesis, remodelling, and comparative histology. Conclusion: Bone histomorphological assessment is an effective method for species identification, gender determination and age estimation by fragmentary osseous remains.