Hsu E S, Patwardhan A G, Meade K P, Light T R, Martin W R
Department of Orthopaedic Surgery, Loyola University Medical Center, Maywood, Illinois 60153.
J Biomech. 1993 Nov;26(11):1307-18. doi: 10.1016/0021-9290(93)90354-h.
The mechanical strength of the human radius and ulna depends on their geometrical and material properties. This study quantifies the cortical bone cross-sectional properties of the adult radius and ulna (cross-sectional area, thickness, centroids, area moments of inertia and section moduli) using computerized tomographic (CT) scanning coupled with image processing along the lengths of eight human cadaveric forearms. Bone mineral mass and apparent ash density were also quantified at serial locations. Sites of significant variation of selected geometric and mineral properties along the length of each forearm bone were determined. Our results show that interpolation of CT measurements made at 10 and 30% of the radial length in the radius and 30 and 90% of the radial length in the ulna can provide approximate geometric values over the 10-90% region. This information can be used to develop a protocol using the fewest sites to clinically assess changes in forearm bone geometry. Regression analyses did not show significant linear relationships between geometric properties and apparent cortical ash density. Thus, CT derived geometric properties are not helpful in estimating the extent of changes in bone density. Area moment of inertia results suggest that the junction of the middle and distal third of the radius, and the ulnar shaft region may have increased vulnerability to fractures. The former is likely due to the change in moment of inertia values, whereas the latter is due to the relatively small magnitude of cross-sectional moments along the ulnar shaft as compared to the proximal or distal ends. This is consistent with fracture patterns observed clinically when a single forearm bone is fractured: Galeazzi fracture of the radius and nightstick fracture of the ulna.
人类桡骨和尺骨的机械强度取决于它们的几何和材料特性。本研究使用计算机断层扫描（CT）并结合图像处理技术，对八具人类尸体前臂全长的成年桡骨和尺骨的皮质骨横截面特性（横截面积、厚度、形心、面积惯性矩和截面模量）进行了量化。还对连续位置的骨矿物质质量和表观灰密度进行了量化。确定了每根前臂骨长度上选定几何和矿物质特性的显著变化部位。我们的结果表明，在桡骨长度的10%和30%以及尺骨长度的30%和90%处进行的CT测量插值，可以在10%-90%的区域内提供近似的几何值。这些信息可用于制定一种方案，使用最少的部位来临床评估前臂骨几何形状的变化。回归分析未显示几何特性与表观皮质灰密度之间存在显著的线性关系。因此，CT得出的几何特性无助于估计骨密度变化的程度。面积惯性矩结果表明，桡骨中、远三分之一交界处以及尺骨干区域可能更容易发生骨折。前者可能是由于惯性矩值的变化，而后者是由于与近端或远端相比，尺骨干沿线的横截面矩相对较小。这与临床观察到的单根前臂骨骨折时的骨折模式一致：桡骨盖氏骨折和尺骨警棍骨折。
