You know what they say about men with big feet? 

Well, try looking at their index finger instead.

A man’s hand could reveal more about what he is hiding under his trousers than you might expect, one medic claims.

According to NHS surgeon Dr Karan Rajan, the shorter a man’s index finger is against his ring finger, the bigger his penis.

Dropping the revelation on TikTok, in a video with more than 915,000 views, he said: ‘This is known as the second to fourth digit ratio, calculated by dividing the length of the index finger by the length of the ring finger.

According to NHS surgeon Dr Karan Rajan, the shorter a man’s index finger is against his ring finger, the bigger his penis

Dropping the revelation on TikTok, in a video with more than 915,000 views, he said: ‘This is known as the second to fourth digit ratio, calculated by dividing the length of the index finger by the length of the ring finger’

He added: ‘The smaller the index finger, the lower the 2D:4D ratio.

‘A smaller digit ratio points to high exposure to testosterone in the uterus.

‘According to the study, testosterone doesn’t just control future penis length but also future finger length.’

But this is not a ‘hard and fast rule’, explained Dr Rajan, who is based in Dorset.

‘It’s an interesting study but by no means a rule book,’ he added.

A 2011 study by Korean researchers compared the difference in finger length of 144 men and measured it against the length of their penises when it was flaccid and stretched. They found that the 2D:4D ratio ‘can predict adult penile size’. 

The study only measured fingers on the right hand because researchers claim ‘there are numerous reports that differences between the sexes in digit ratio are greater on the right hand than on the left’. 

Writing in the Asian Journal of Andrology, they also said that ‘the right hand may be more sensitive to the influence of testosterone’.

But hands are not the only body part which has been connected with a man’s length.

In support of the ‘big nose, big hose’ theory, a scientific study found men with larger noses have longer penises.

Japanese researchers last month found men with the biggest noses had a ‘stretched penile length’ of 13.4cm, or well over five inches, on average.

Those with smaller noses had penises that measured 10.4cm, or four inches.  

Nothing will make a man’s penis any larger or smaller, according to the NHS.

HOW CAN YOU MEASURE YOUR 2D:4D RATIO?

To measure your finger straighten it and look at the palm of your hand. 

At the base of your index and ring fingers there are likely to be creases. Your index finger is likely to have one crease, the ring finger is a band of creases. 

Select the crease closest to the palm and choose a point on the crease midway across the base of the finger. 

Mark it with a pen. Measure it from the mark to the tip of the finger.  

To measure your finger straighten it and look at the palm of your hand. At the base of your index and ring fingers there are likely to be creases. Your index finger is likely to have one crease, the ring finger is a band of creases