足横弓三维形态的生物力学意义

3-D Morphological and Biomechanical Study of the Transverse Arch of the Foot

目的：通过对足横弓放松和负重状态时的三维形态分析，结合５个跖骨头在后跟略离地和抬起时的负重分布，探讨足横弓形态生物力学意义。材料和方法：在前足放松和负重状态下对５个跖骨进行ＣＴ连续横断扫描，而后在ＣＴ工作站上进行图像三维重建，在三维重建图像上观察足横弓形态变化。另外利用压敏片法测量足底５个跖骨头和趾在足跟略离地面、足跟完全抬起时的负重分布。结果：足横弓负重后有不同程度的弧度压低，但多仍保持一定的弧度；足跟略离地时中央跖骨头负重比例小于两侧跖骨头，而在足跟完全抬起时负重明显增大。结论：组成足横弓的５个跖骨头均是重要的负重结构。

Objective: To study the biomechanical mechanism of the 3-D configuration of the transverse arch of the foot. Methods: Serial transverse CT scanning of 5 metatarsals were made under condition of the heel release and bearing weight of the metatarsal heads. Then the CT images were processed in the CT working station to reconstruct 3-D images of the transverse arch. On the 3-D images, the changes of the shape of the transverse arch were analyzed. The load distribution under 5 metatarsals and hallux were measured by the help of the pressure sensitive film under condition that the heel began to lift and totally lift. Results: The transverse arch of the foot lowered to various extent during bearing weight. Thecentral metatarsals bore less proportion of load than the lateral ones when the heel began to lift, but more proportion of the load during total lift of the heel. Conclusions: Each metatarsal was an important weight- bearing structure, and bore different proportion of weight in different gait phase.