Abstract
Introduction: Finger length ratio (2d:4d) is a sexually dimorphic trait. Smaller, more masculine second digit (index finger) to fourth digit (ring finger) ratio’s are associated with higher exposure to prenatal testosterone levels or greater sensitivity to androgens, or both. People with smaller finger ratios are perceived as being more masculine and dominant by female observers. Smaller ratios have also been associated with an increased propensity to engage in aggressive behaviour. We examined the relationship between Boxer’s fractures, a traditional injury of aggression and finger length ratio.
Methods: We reviewed 1123 patient records and/or hand x-rays over a seven month time frame showing 123 fifth metacarpal (Boxer’s) fractures. We then measured, using recorded radiological data, the distance in millimetres from the base of the proximal phalanx to the tip of the distal phalanx for the second, third and fourth fingers. We also recorded sex, side of injury, site of injury and mode of injury.
Results: 123 Boxer’s fractures were found over a seven month time period, 110 male and 13 female. 67.27% were right sided. The average age was 27.6 yrs ±14.2. The average finger length ratio (proximal phalanx to distal phalanx) for males was 0.9 and for females was 0.94.
Conclusion: Smaller second digit to fourth digit ratios are positively associated with persons presenting with fifth metacarpal fractures, thereby indicating increased aggressive tendancies independently of gender.
Correspondence should be addressed to Mr Richard Wallace at Musgrave Park Hospital, 20 Stockman’s Lane, Belfast BT9 7JB, Northern Ireland.
