Department of Plastic and Reconstructive Surgery, National University of Ireland, Galway, Ireland.
Injury. 2013 Nov;44(11):1636-9. doi: 10.1016/j.injury.2013.07.018. Epub 2013 Aug 6.
Upper limb second to fourth digit ratio (2D:4D) has been shown to be dependent on prenatal androgen exposure. A longer relative fourth digit to second digit is indicative of increased intrauterine testosterone exposure prenatally and the converse is also true for oestrogen exposure. The 2D:4D ratio has implications in the sporting, academic, financial and sexual arenas. The purpose of this study was to examine the association between smaller finger length ratios (2D:4D) and boxers fractures, in both men and women, by comparing the 2D:4D ratios in 150 boxers fractures and comparing them to matched controls. Boxers fractures are an injury classically incurred during acts of aggression and we postulated that this cohort of patients would have a smaller 2D:4D ratio in comparison to the normal population mean ratio.
One hundred and fifty radiographs from patients with boxers fractures secondary to aggressive actions were analysed and the 2D:4D ratio was calculated. A further 150 X-rays from patients not involved in aggressive activities were used as a control group and the 2D:4D ratio was calculated in the same manner. We then performed statistical analysis to compare the 2D:4D ratios between our two groups.
As predicted, the 2D:4D in males was smaller than females in all of the groups. However, our results showed that those presenting with a boxers fracture due to an aggression related injury had a statistically significant smaller 2D:4D ratio when compared to the normal population.
Boxers fractures are injuries that typically occur from an aggressive act. It is well documented that a low 2D:4D ratio is reflective of an increased prenatal exposure to androgens, particularly testosterone. We have shown that boxers fractures are associated with a smaller 2D:4D ratio than the normal population, thus suggesting that persons exposed to high levels of prenatal androgens are more likely to exhibit aggressive tendencies in adulthood. Our results suggest that smaller digit ratios may predict a predisposition to acts of aggression, and as such result in an increased likelihood of sustaining an injury such as a boxers fracture. This relationship seems to be present independently of gender.
第二至第四指的相对长度（2D：4D）与胎儿期雄激素暴露有关。相对第四指比第二指较长表明胎儿期的睾丸激素暴露增加，而雌激素暴露则相反。2D：4D 比值在运动、学术、金融和性领域都有影响。本研究的目的是通过比较 150 例拳击手骨折患者和 150 例匹配对照的 2D：4D 比值，检查男性和女性的较小手指长度比值（2D：4D）与拳击手骨折之间的关系。拳击手骨折是一种典型的在攻击性行为中发生的损伤，我们推测，与正常人群的平均比值相比，该患者群体的 2D：4D 比值会更小。
对 150 例因攻击性动作导致拳击手骨折的患者的 X 射线进行分析，并计算 2D：4D 比值。还对 150 例未参与攻击活动的患者的 X 射线作为对照组进行分析，并以同样的方式计算 2D：4D 比值。然后，我们进行了统计分析，比较了两组的 2D：4D 比值。
正如预期的那样，在所有组中，男性的 2D：4D 比值均小于女性。然而，我们的结果表明，那些因与攻击性损伤相关的拳击手骨折的患者，其 2D：4D 比值与正常人群相比具有统计学意义上的显著较小。
拳击手骨折是一种典型的由攻击性行为引起的损伤。有充分的文献证明，低 2D：4D 比值反映了胎儿期雄激素暴露增加，特别是睾丸激素暴露增加。我们已经表明，拳击手骨折与正常人群相比，2D：4D 比值更小，这表明暴露于高水平的胎儿期雄激素的人在成年后更有可能表现出攻击性倾向。我们的结果表明，较小的指比率可能预示着有攻击性倾向，因此，更有可能导致拳击手骨折等损伤。这种关系似乎独立于性别存在。
