Skeletal Biology and Forensic Anthropology Research Group, School of Archaeology and Anthropology, Australian National University, Canberra, Australia.
Australian Research Centre for Human Evolution, Environmental Futures Research Institute, Griffith University, Brisbane, Australia.
Anat Sci Int. 2021 Jun;96(3):386-399. doi: 10.1007/s12565-020-00601-8. Epub 2021 Jan 22.
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 the hypothesis that rib tissue will be well vascularized and thus enhance susceptibility to metabolic influence. An intra-skeletal comparison of bone vascular canal density was conducted using a macropod animal model adapted to bipedal habitual hopping. The right humerus, ulna, radius, femur, tibia, fibula, a mid-thoracic and upper-thoracic rib of an eastern grey kangaroo (Macropus giganteus) were sectioned at the midshaft, from which histological sections were prepared. Bone vascularity from a maximum of 12 mm of sub-periosteal parallel-fibred and lamellar bone was recorded, resulting in a total of 2047 counted vessels. Vascular canal density data were corrected by cortical width, maximum length, and midshaft circumference robusticity indices computed for each bone. The fibula consistently had the highest vascular canal density, even when corrected for maximum length, cortical width and midshaft circumference robusticities. This was followed by the mid- and upper-thoracic ribs. Vascularity differences between bones were relatively consistent whether vascular canal density was controlled for by cortical width or midshaft circumference robusticities. Vascular canal density and robusticity indices were also positively and negatively correlated (p < 0.05). Results confirm that the ribs are well vascularized, which facilitates bone metabolic processes such as remodelling, but the fibula also appears to be a well vascularized bone. Future research investigating human bone metabolism will benefit from examining thoracic rib or fibula samples.
人们认为，与四肢骨骼相比，肋骨在微观层面上受到的机械应变较小，这意味着肋骨重塑更好地反映了骨骼的生理稳态。在这里，我们检验了这样一个假设，即肋骨组织将具有良好的血管化程度，从而增强对代谢影响的敏感性。我们使用适应两足习惯性跳跃的有袋动物模型对骨骼内血管密度进行了骨骼内比较。对一只东部灰袋鼠（Macropus giganteus）的右肱骨、尺骨、桡骨、股骨、胫骨、腓骨、中段和上段肋骨进行了骨干中部的切片，从这些切片中制备了组织学切片。从最大 12 毫米的骨膜下平行纤维和板层骨中记录了骨血管的数量，总共记录了 2047 个血管。通过为每个骨骼计算的皮质宽度、最大长度和骨干中部周长粗壮度指数，对血管密度数据进行了校正。即使在考虑了最大长度、皮质宽度和骨干中部周长粗壮度后，腓骨的血管密度仍然最高。其次是中段和上段肋骨。无论血管密度是通过皮质宽度还是骨干中部周长粗壮度来控制，骨骼之间的血管差异都相对一致。血管密度和粗壮度指数之间也呈正相关和负相关（p<0.05）。结果证实肋骨具有良好的血管化程度，这有助于骨骼代谢过程，如重塑，但腓骨似乎也是一种血管化良好的骨骼。未来研究人类骨骼代谢将受益于检查胸肋骨或腓骨样本。
