Note that only my pinky and first finger bar is doing anything here, the other two are off the strings.
Now being able to do this with your pinky is really handy, because using three fingers to fret root 5 chords is slow and often inaccurate. But look at that poor pinky, the top joint (wikipedia tells me it is the Distal Interphalangeal Joint) is bent backwards, and the middle joint is pushing it hard up against the frets. If I push too hard, too many times, for too long, I strain it. My G chord fretting is similar, I often fret the top G with the D on the second string using pinky. Like this:
Don't be fooled, my third finger isn't on a string - 3rd and 4th strings are open. But as you can see, it is the same principle. I love the sound of a G chord with the D added!
Another thing I do with my pinky is stretch it out to fret a low F and a high A. It's an F chord...well, bass note is F, high A, second string C and third string A. Fourth and Fifth are muted. Yeah, I know, the photo doesn't look like it:
Your pinky is probably the weakest finger you own, and yet, for the guitar, I rate it as the second most useful finger after your index finger. So, we should probably take care of it.
So to reduce the amount of abuse I throw at the poor little fella, I try to observe the following, with varying degrees of success:
- Don't keep practicing the same song over and over, where it features the same pinky (or any other finger) abusing chord structures. That is a recipe for strain.
- Avoid pinky abuse. If you watch Naudo, you can see he does a lot of strange fretting and I think it is partly to reduce finger strain. Don't put pinky in nasty positions, try other fretting. I should have trained in this fretting technique with my ring finger rather than pinky.
- If it is starting to hurt, stop. I once did some damage to my hand "pushing through the pain" that took the better part of a year to recover from. Enough said, there is always tomorrow.
- If you do strain it, rest it. Anti-inflammatory drugs will help, but let me throw a hippy cure which works for me - quarter of a teaspoon of turmeric stirred into water once a day. I've been doing it for years since initially hurting pinky, I'm sure it's made a difference. A proper scientist would stop taking it as a control, to see if the issue returns, but I don't want it to return even if turmeric is just a placebo!
Be careful out there!