Undoing a woman's bra can cause men serious finger injuries more associated to dangerous sports such as rock-climbing, medical experts claimed on Friday.

Plastic surgeons from St George's Hospital in London say up to 40 per cent of young men risk injury to their digits by failing to grasp how to undo the clasp.

In one such case, a man suffered a broken finger and severe ligament damage after catching it as he tried to unhook his lover's bra.

The patient's surgeon, Andrew Fleming, said: "It was a very nasty injury... the type of thing that is more commonly associated with sport, particularly rock climbing."