Intra-skeletal vascular density in a bipedal hopping macropod with implications for analyses of rib histology

Human ribs are thought to be less affected by mechanical strain at the microscopic level than limb bones, implying that rib remodelling better reflects bone physiological homeostasis. Here, we test hypothesis tissue will well vascularized and thus enhance susceptibility metabolic influence. An intra-skeletal comparison of vascular canal density was conducted using a macropod animal model adapted bipedal habitual hopping. The right humerus, ulna, radius, femur, tibia, fibula, mid-thoracic upper-thoracic an eastern grey kangaroo (Macropus giganteus) were sectioned midshaft, from which histological sections prepared. Bone vascularity maximum 12 mm2 sub-periosteal parallel-fibred lamellar recorded, resulting in total 2047 counted vessels. Vascular data corrected cortical width, length, midshaft circumference robusticity indices computed for each bone. fibula consistently had highest density, even when width robusticities. This followed mid- ribs. Vascularity differences between bones relatively consistent whether controlled or also positively negatively correlated (p < 0.05). Results confirm vascularized, facilitates processes such as remodelling, but appears Future research investigating human metabolism benefit examining thoracic samples.