Peter Attia· MD
well trigger finger is what we were talking about before where the inflammation of the sheath uh and then right in the middle here there's a series of pulleys and these are super cool I'm going to draw a picture if I may yeah okay so we're looking at the side of the hand yeah so we're looking and let's just say this is the middle finger um it's the longest and this is the metacarpal this is the first of the three bones of the finger proper and what I've drawn here this black line coming underneath is the flexor tendon and that's the one that does curls all our curl allows you to do all your pull-ups and so there's four bones there just so people can see you know I don't want them to miss the one this one is kind of hidden within the hand because that's through here yeah and so then there's the three successive and so if you just if you had a muscle attached to this and you pulled on it and didn't have those blue structures then this would bow string just like a fishing pole if you don't have if you don't put your the fishing line through the eyelets then it just stays way away yeah and it's actually stronger that way but you lose all the mobility so you you lose the capacity to really curl your fingers tightly so that's what they're gliding through and those are fibro osseous tunnels um and just fibrous tissue very strong and which you were mentioned rock climbing they can rupture because you're putting so much force on those in such funky positions and isolating two fingers one finger and so forth so I see that a lot in rock climbers but the the point here is that as you're rubbing constantly going back and forth whether you're playing a concerto or you're rock climbing you can get inflamed along that sheath this particular pulley here is down in the palm and that's the most common sight to have inflammation to where you can even get some nodular swelling in the tendon and that thickening up of that pulley and then it just actually catches and we call it a trigger finger because it's like a pulling a trigger on a gun it it it has that feeling so so that's and we frequently have to inject those with Cortisone and frequently have to operate on their ubiquitous and about half of them recover with just a cortisone injection yeah I always say actually more in the order depending on how if we get to them if you take someone who presents within say six weeks of onset there's about a 75 cure rate with one or two injections okay so the longer you wait the more likely potential damage you cause and the more chronic inflammation that ensures correct but we don't and this applies kind of a general consensus something we talked about this before when we were talking about cortisone shots is in these types of soft tissue procedures we don't keep injecting cortisone cortisone cortisone because it can lead to soft tissue degradation and ultimately even tendon ruptures I've never seen one in my practice but we know they can exist and what do you use as a rule of thumb for how many times you'll put three three at three in the lifetime of the joint three in the lifetime of that tendon sheath unless it's very very broad usually you don't see someone back 10 years later who needs another injection but if I did I'd be willing to do that again because everything has normalized physiologically at that point now the other cool thing that I was talking about before when we were talking about the you ask about the extensors versus the flexors so if we look at the red but this is the extrinsic extensor tendon that will straighten up the knuckles but then we look further out and we see well that only stops that tendon stops at the middle knuckle but what allows what pulls the whole finger straight and it's actually this intrinsic muscle here that's tapering down and has a very thin tendon it turns into a lateral band and it travels from the Palm side up above the middle knuckle above that axis of rotation and then it goes all the way out and attaches to the tip and so it's a super cool mechanism that through a series of mechanical placements it's able to extend the finger even though by Contracting Yeah by Contracting it's straightening up the finger it's super cool yeah and so but but it doesn't take much like if you take a a direct blow to that knuckle right there and that tendon just slips because you've disrupted some soft tissue it can slip below the axis of rotation then it