Anatomy: finger strength

Twice at safety meetings (the corporate office of a mining corporation) we’ve been told something that screams folklore or UL to me but I’d like to be sure. In the discussion of carpal tunnel syndrome we’ve been informed that our pinky and ring fingers are capable of a stronger grip than our index and middle fingers. The reason given is that the muscles that flex the index and middle finger are in the forearm while those for the ring and pinky extend all the way through our arms and down into the torso toward the hip. WTF? I’ve studied “flayed man” every time I’m in the doctor’s office but haven’t seen this.

The demonstration of this is to stand with arm extended holding a large marker pen, first gripping with one pair then the other. A second person pushes on the pen. Lots of people say they can see the difference but I really think that’s because people are highly suggestable. I don’t see a significant difference.

WTF indeed. That is completely false. The muscles for the ring and pinky fingers are in the forearm, exactly the same as the index and middle fingers.

Here’s a link to Gray’s Anatomy. I don’t understand half of the words used, but it has some nice illustrations that clearly show where the muscles for the four fingers are anchored (scroll down a ways).

Anecdotally, I would say that it seems true. I feel like I can grip harder with those fingers.
IMHO, as you suspect, the explanation for this is totally untrue. I think it’s more to do with using the base of the thumb as an opposable grip. I’d be interested to hear from someone in the medical profession!

FWIW the thumb doesn’t appear to be a factor. It is held out of the way while the fingers grip against the palm.

Joe Random, thanks for the link.

The ring and pinkie together might be capable of a stronger grip than my index or middle, but not seperately.

A little clarification is needed. The way the test was done the pinky and ring finger grip at the same time as do the index and middle. The test is done by standing and extending the arm fully level with the ground. Hold something like a magic marker, gripping only with two fingers at a time. A second person used the marker to try and push the subject back and forth.

First, for what it adds, when playing the strings on the stand up bass, you use your first finger, your second finger, and you use your third and forth fingers together. This says to me that alone, each of these fingers is not strong enough to provide enough oomph to press down the string. (Those babies are thick and hard to move). At the same time, because your thumb is on the backside of the fingerboard, the movement is still in some measure opposed to the thumb.
Second, why in the hell would we be surprised that some muscles are better developed than others? After a lifetime of use some muscles do become stronger than others. Check out your biceps and tricpes, for example. I think the concept is correct - that the last two fingers can apply more force than the first two, and I think it’s mostly because of the way they are used - opposed to the thumb - and the amount of use they get. That’s my thinking and I’m sticking with it. xo C.

Hey, great link. Does anyone know if the forearm front is the topsdie fo the wrist or the bottomside? I can’t tell if it’s the front or the posterier forearm view that is palmside up. When I wiggle my fingers, I see the tendons on the back of my hand move and the muscles in the underside of my wrist flex and I’d like to match the muscles to the illustration.

And I can tell you from personal experience that all your fingers are anchored. I row and have a tendency to overgrip (grip too tightly). I also tend to shift fingers depending on which fingers have the worst blisters. No matter what fingers I use, I usually get aching deep in my forearms, along the underside and down by the elbow…

Anatomical position would be if you held your arms down and out to your side with your palms facing forward and the fingers extended. So the the palms are anterior (front) and back (dorsum) of the hand is posterior. Fig 418 in Gray’s is the posterior (back) of the forearm.

Most of the muscles in the anterior forearm are flexors which you would use to grip things. The muscles of the posterior forearm are extensors to open your hand.
I dissected the forearm in med school anatomy class about 3 months ago. It’s pretty cool if you think about the mechanics of the arm/fingers. Its amazing to think of all the stuff you can do with your hands.