I always liked to hit a hard heavy bag for that reason, but my hands are a mess. My middle and index knuckles are very large, while the knuckles on my small, outside fingers have not been seen in years. I think that, on my right hand, part of the knuckle between the middle and small knuckles is actually under the middle knuckle.
It is very important to be aware of which knuckles your punches are landing on- this affected by proper punching technique and understanding how to utilize that technique at different distances. Nobody ever bothered to tell me this and it took me some time to figure it out for myself.