Damage to Knuckles
 

As we all know it is almost a law that every cinematic brawler have invulnerable knuckles. Yet for those who do not wish that is there a way to do injury to the fists in a brawl? Or has that already been allowed for?

Re: Damage to Knuckles
 

See "Harsh Realism for Unarmed Fighters," Martial Arts p124. This has a few options other than what's in the Basic Set.

If you're referring to fists getting injured in an ordinary fight just from punching the guy (but not in the skull), I'd say such minor injury is well below the GURPS level of resolution. Your knuckles might be sore after giving someone a beating, but they aren't going to really be injured unless you really screwed up (critical failure).

Re: Damage to Knuckles
 

If you don't have MA, there's a small section called Hurting Yourself on B379 that might apply.