Specht T E, Miller G J, Colahan P T
Department of Surgical Sciences, College of Veterinary Medicine, University of Florida, Gainesville 32610-0116.
Am J Vet Res. 1990 Aug;51(8):1242-6.
The breaking strength (stress at failure) of equine third metacarpal bones, with and without clustered drill holes, was determined in vitro. Paired ossa metacarpalia II-IV of 39 horses (n = 39) between 2 and 7 years old were tested in palmarodorsal 3-point bending. Four treatments were compared. Clustered 2.7- or 3.5-mm drill holes, in a 4- or 7-hole pattern, were made in the dorsal cortex of the distal diaphysis of the left third metacarpal bone. Undrilled right third metacarpi were used as controls. Bones with clustered drill holes failed by an oblique fracture through 1 or more drill holes, whereas undrilled bones failed with a middiaphyseal transverse fracture. Clustered drill holes acted as a stress concentrator and significantly (P less than 0.05) decreased the stress required for failure. However, differences in breaking strength between treatment groups were not significant (P greater than 0.05).
在体外测定了有无成组钻孔的马第三掌骨的断裂强度（破坏应力）。对39匹2至7岁马的掌骨II-IV进行配对，在掌背位进行三点弯曲试验。比较了四种处理方式。在左第三掌骨远端骨干的背侧皮质上制作成组的2.7毫米或3.5毫米钻孔，钻孔模式为4孔或7孔。未钻孔的右第三掌骨用作对照。有成组钻孔的骨头通过斜穿1个或多个钻孔而发生骨折，而未钻孔的骨头则发生骨干中部横向骨折。成组钻孔起到了应力集中器的作用，显著（P小于0.05）降低了破坏所需的应力。然而，各处理组之间的断裂强度差异不显著（P大于0.05）。
