A record number of men needed NHS surgery after snapping their penises last year, according to statistics.

In total, 164 men had to have an operation to save their manhood after fracturing the blood-filled columns which make it hard during an erection.

Men in their 30s and 40s were most affected by the painful injury but the youngest patient was just 18, while the oldest was in his 70s.

When a penis fractures it most often happens during sex, snapping under the weight of a partner's body or a powerful thrust.

A scientific study in 2015 revealed the cowgirl (woman on top), doggy style and missionary positions were most likely to cause injury.

In total, 164 men had to have an operation to save their manhood last year after fracturing the blood-filled columns which make it hard during an erection (stock image)

The number of men needing penis repair surgery last year was 38 per cent higher than in 2014/15 and a record number, according to The Sun.

And there may be even more cases among men who are too embarrassed to go to a doctor about it, one expert said.

The anatomy of an erection is based around two spongy tubes which fill up with blood and harden, and a firm, fibrous sheath which surrounds them, called the tunica albuginea.

When the tunica albuginea, which is made mostly of collagen, comes under extreme pressure it can snap and cause the penis to bend out of shape.

If this happens the erection will quickly subside and the penis become swollen and painful. The penis can even make an audible cracking sound when it breaks.

It usually happens if the penis is thrust into a solid surface or if something – or someone – falls on it.

'Normally patients coming with something looking like a bruised aubergine,' King's College Hospital urologist Gordon Muir told The Sun.

'If you leave it to health without treatment there is a high chance of getting scarring which can lead to Peyronie's disease.'

Peyronie's disease is a condition in which scar tissue builds up inside the penis and causes it to bend dramatically rather than stay straight – a slight bend is normal but Peyronie's may cause it to be 90° or more.

A fractured penis can usually be repaired with surgery to stitch the tunica albuginea back together.