BONE STRESS IN THE HORSE FORELIMB DURING LOCOMOTION AT DIFFERENT GAITS - A COMPARISON OF 2 EXPERIMENTAL METHODS
BONE STRESS IN THE HORSE FORELIMB DURING LOCOMOTION AT DIFFERENT GAITS - A COMPARISON OF 2 EXPERIMENTAL METHODS
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DOI：
10.1016/0021-9290(83)90107-0
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发表时间：
1983-01-01
影响因子：
2.4
通讯作者：
LANYON, LE
中科院分区：
文献类型：
--
作者：
BIEWENER, AA;THOMASON, J;LANYON, LE
本文用两种独立的方法同时测定了作用于马桡骨头侧和尾部皮质以及掌骨背侧和掌侧皮质的纵向应力。一种方法涉及使用玫瑰花形应变计记录体内骨应变;另一种方法涉及拍摄马的前肢通过测力板时的位置。两种分析之间的一致性对于桡骨比对于掌骨好。两种方法均显示桡骨主要以矢状弯曲加载，使尾侧皮质处于压缩状态，而颅侧皮质处于拉伸状态。在每次步态中，基于薄膜/力分析的每个皮质中的峰值应力的大小比从骨应变记录确定的高1.5-2倍。在掌骨中，从膜/力方法计算的每个皮质中的应力的大小在每个步态中比骨应变记录所示的大2-3倍。然而，尽管胶片/力分析表明掌骨以矢状弯曲方式加载（使掌侧皮质处于压缩状态，背侧皮质处于拉伸状态），但骨应变记录显示掌骨在每次步态时主要以轴向压缩方式加载。由于膜/力法依赖于肢体节段相对于地面反作用力方向的准确测量，弯矩计算中的相对较小误差可能导致确定作用于骨皮质的应力水平和分布的显著差异。通过2种方法获得的掌骨载荷的差异可以部分地由生物力学模型的简单性来解释，例如，忽略了由籽骨对掌骨远端施加的力。从体内骨应变记录确定的应力记录表明，尽管步态发生变化，但每个骨都受到一致的载荷机制。这种一致的应变分布应允许这些骨在使用支撑所施加的动态载荷所需的组织时最大化经济性。在以恒定速度运动期间，从桡骨中的骨应变记录测量的峰值应力（-40.8 ± 0.01）。4.1 MN m-2）明显大于掌骨（-25.1 . ±-. 2.8 MN m-2），不考虑速度和步态。然而，在加速和减速过程中，掌骨的峰值应力急剧上升（-40.6 . ±. 3.4 MN m-2），但在半径上保持恒定（-37.8 . ±. 5.8 MN m-2）。当考虑到可能导致最高应变的常见载荷条件时，两种骨具有相似的失效安全系数。
Longitudinal stresses acting in the cranial and caudal cortices of the radius and the dorsal and palmar cortices of the metacarpus in the horse were determined using 2 independent methods simultaneously. One approach involved the use of rosette strain gauges to record in vivo bone strain; the other involved filming the position of the horse''s forelimb as it passed over a force plate. Agreement between the 2 analyses was better for the radius than for the metacarpus. Both methods showed the radius to be loaded primarily in sagittal bending, acting to place the caudal cortex in compression and the cranial cortex in tension. At each gait the magnitude of peak stress in each cortex based on the film/force analysis was 1.5-2 times higher than that determined from the bone strain recordings. In the metacarpus, the magnitude of stress in each cortex calculated from the film/force method was 2-3 times greater at each gait than that shown by the bone strain recordings. However, whereas the film/force analysis indicated that the metacarpus was loaded in sagittal bending (acting to place the palmar cortex in compression and the dorsal cortex in tension), the bone strain recordings showed the metacarpus to be loaded primarily in axial compression at each gait. Because the film/force method depends on an accurate measure of limb segment orientation relative to the direction of ground reaction force, comparatively small errors in calculations of bending moments may lead to a significant difference in the level and distribution of stress determined to act in the bone''s cortices. The discrepancy in metacarpal loading obtained by the 2 methods may be explained in part by the simplicity of the biomechanical model which, for instance, neglected the force exerted by the sesamoids on the distal end of the metacarpus. The records of stress determined from the in vivo bone strain recordings showed that each bone was subjected to a consistent loading regime despite changes of gait. Such a consistent strain distribution should allow these bones to maximize economy in the use of tissue required to support the dynamic loads applied. Peak stresses measured from the bone strain recordings in the radius during locomotion at constant speed (-40.8 .+-. 4.1 MN m-2) were significantly larger than those in the metacarpus (-25.1 .+-. 2.8 MN m-2), regardless of speed and gait. During acceleration and deceleration, however, peak stress rose dramatically in the metacarpus (-40.6 .+-. 3.4 MN m-2) but remained constant in the radius (-37.8 .+-. 5.8 MN m-2). When the commonly encountered loading conditions likely to cause the highest strains are taken into account, both bones have similar safety factors to failure.