The length of your fingers can reveal how likely you are to develop arthritis, a new study has found.
People with shorter index fingers than ring fingers have almost double the chance of suffering from osteoarthritis, findings show.
Researchers at the University of Nottingham said this was an "intriguing observation" that could help doctors diagnose risk factors in patients.
Men generally have this finger length pattern while most women have the same length ring and index fingers, according to the researchers. But men were not more likely to get osteoarthritis because of their finger length - scientists said there were other factors.
Among them were family history, being overweight, age and gender - women generally were more likely to get arthritis, said lead researcher Prof Michael Doherty.
Women with a "male" finger pattern had a combined risk factor and researchers found that these women were more likely to develop osteoarthritis of the knee than men.
Prof Doherty said: "It's an intriguing observation. It can be used as another way of totting up a scale of how likely you are to get osteoarthritis - it's another way of checking. We used X-rays in our study, but doctors could just do it with a simple hand examination."
He said that it was well known that the ratio between the second and fourth fingers, referred to as 2D:4D, had an impact on the body's hormones. People with smaller 2D:4D ratios can have higher prenatal testosterone levels, lower oestrogen concentrations and higher sperm counts.
He said people with a lower 2D:4D ratio were usually better at sport and were generally more aggressive.
Now the 2D:4D ratio has uncovered links to arthritis. He added: "The 2D:4D length ratio appears to be a new risk factor for the development of osteoarthritis. Specifically, women with the 'male' pattern of 2D:4D length ratio - that is, ring finger relatively longer than the index finger - are more likely to develop knee osteoarthritis."
The study of more than 2,000 people into the impact of the ratio of finger lengths and its relation to osteoarthritis is the first of its kind.