Horsman A, Leung W K, Bentley H B, McLachlan M S
Br J Radiol. 1977 Jan;50(589):23-8. doi: 10.1259/0007-1285-50-589-23.
Ten humeri and ten femora were radiographed in nine positions of longitudinal rotation. In each position total, medullary and cortical widths of the diaphyses (TW, MW, CW) were measured to assess the effect of rotation on these dimensions. The results were expressed as differences from the values in the neutral position (delta TW, delta MW, delta CW). In the humerus, medial rotation produced greater changes than lateral rotation. Though rotation in either direction increased CW, the systematic error due to medial rotation to only 5 degrees (approximately +0.0058 cm per degree) was more than double that due to lateral rotation. In the femur, lateral rotation had the greater effect, producing a marked decrease in CW (approximately -0.0072 cm per degree). Medial rotation produced only a slight increase in CW. The ratios CW/TW ("cortical index") and CA/TA ("area ratio") were calculated and expressed as differences from the values in the neutral position (delta CW/TW, delta CA/TA). Rotation affected these variables much less than the linear dimensions. Furthermore, through the variance of delta TW, delta MW and delta CA/TA increased only slightly or not at all. These results suggest that if radiographic morphometry is to be applied to the humerus and femur, these ratios rather than transverse dimensions should be used. Sequential changes in CW may be totally obscured by small rotational errors.
对10根肱骨和10根股骨进行了9个纵向旋转位置的X线摄影。在每个位置测量骨干的总宽度、髓腔宽度和皮质宽度（TW、MW、CW），以评估旋转对这些尺寸的影响。结果表示为与中立位置值的差值（ΔTW、ΔMW、ΔCW）。在肱骨中，内旋产生的变化比外旋大。尽管向任一方向旋转都会增加CW，但内旋仅5度时产生的系统误差（约每度+0.0058厘米）是外旋的两倍多。在股骨中，外旋的影响更大，导致CW显著降低（约每度-0.0072厘米）。内旋仅使CW略有增加。计算了CW/TW（“皮质指数”）和CA/TA（“面积比”）的比值，并表示为与中立位置值的差值（ΔCW/TW、ΔCA/TA）。旋转对这些变量的影响远小于线性尺寸。此外，ΔTW、ΔMW和ΔCA/TA的方差仅略有增加或根本没有增加。这些结果表明，如果要将X线形态测量应用于肱骨和股骨，应使用这些比值而非横向尺寸。CW的连续变化可能会被小的旋转误差完全掩盖。
