Differences in compact bone tissue microscopic structure between adult humans (Homo sapiens) and Assam macaques (Macaca assamensis)

This study investigated the osteon structure of adult humans and Assam macaques, which served as a nonhuman primate model, to find an adequate key for species identification. Samples of compact bone from humans (n = 5) and Assam macaques (n = 5) - including humerus (n = 20), radius (n = 20), ulna (n = 20), femur (n = 20), tibia (n = 20) and fibula (n = 20) - were processed using conventional histological techniques. 100 secondary osteons from each sample were evaluated under light microscopy. Parameter measurements included: diameter, perimeter and area of Haversian canal and osteon; distance between centers of Haversian canals; and ratio between diameter of Haversian canal and osteon. Four parameters, including diameters and areas of Haversian canal and osteon, demonstrated significantly higher (P < 0.05) values in humans than in Assam macaques. Therefore, compact bone microstructure could thus be used as a potential tool to differentiate human and nonhuman primates.