The Relationship between Form and Function of the Human Vertebra in Ordinary Posture and Movement.

本研究的目的是利用材料力学和动物实验的方法，探讨人体脊椎骨在正常姿势和运动状态下的形态与功能的关系。52例现代日本人（男26例，女26例）、6例黑猩猩、30例猕猴（日本猴）的第3颈椎至最后腰椎。本研究使用了6只日本serow。此外，还研究了直立双足站立运动对17只生长期雄性大鼠椎体形态学的影响，这些大鼠被分为两组（8个对照组和9个运动组）。以下结果表明了人体脊椎运动与正常姿势之间的关系。(1)腰椎区横截面积（A）和左右轴面积惯性矩（I_x）显著增加。(2)前后轴面积惯性矩（I_y）从第3颈椎到最后一腰椎逐渐增大，在最后一腰椎达到峰值。(3)最大主惯性矩（Imax）从第10胸椎到最后一腰椎显著增加。(4)最小主惯性矩（Imin）从第3颈椎到最后一个腰椎逐渐增大。(5)极惯性矩（I_p）从第11胸椎到最后一腰椎显著增加。(6)截面指数（SI）显示颈、腰椎区域有由圆形向椭圆形变化的趋势。(7)与其他动物相比，人类的所有值均显著增加。结果表明，人的腰椎区具有相当的坚韧和强度，与其他动物相比，它能承受左右弯曲力。

The aim of the present study is to investigate the relationship between form and function of the human vertebra in ordinary posture and movement by using material mechanics and the animal experiment. Vertebrae from the 3rd cervical to the last lumber vertebra of 52 modern Japanese (26 males and 26 females), 6 chimpanzees, 30 macaques (Japanese monkeys). And 6 Japanese serows were used in the present study. Moreover, the effects of an erect bipedal standing exercise on the morphology of vertebral body were investigated in seventeen growing male rats that were divided into two groups (8 controls and 9 exercises). The following results indicate the relationship between ordinary posture and movement of human vertebra. (1) Cross-sectional area (A) and the area moment of inertia of right-left axis (I_x) increased significantly in the lumbar vertebral region. (2) Area moment of inertia of antero-posterior axis (I_y) increased gradually from the 3rd cervical to the last lumbar vertebra, and reached a peak in the last lumbar vertebra. (3) Maximum principal moment of Inertia (I_max) increased remarkably from the 10th thoracic to the last lumbar vertebra. (4) Minimum principal moment of inertia (I_min) increased gradually from the 3rd cervical to the last lumbar vertebra. (5) Polar moment of inertia (I_p) increased remarkably from the 11th thoracic to the last lumbar vertebra. (6) Section index (SI) showed a tendency of shape changes from the circle into oval form in the cervical and lumbar vertebral region. (7) All values significantly increased in the human compared with other animals. Our results showed that lumbar vertebral region of human was considerably tough and strong, and that it could stand especially against the right-left bending force as compared with other animals.