This is what happens inside your body when you flex your fingers
Illustration by Mariana Ruiz Villarreal, released into the public domain
Now bend your fingers at their first joint past the knuckles. Your hand should look a bit like a spider on its back, curling up its legs - that's your proximal interphalangeal joints (PIJs) bending.
Let your hand splay out again. This time, curl just your pointer finger and let it uncurl. Now do your ring finger.
What do you think is going on here? If you had to guess, where would you say the muscle involved is?
Having never taken a medical anatomy course, I'd always assumed it was located entirely in the finger itself, just like the main muscles for flexing your elbow live in your upper arm.
Turns out, this intuition is wrong. The main muscle for flexing your PIJs actually runs all the way up your arm. Called the flexor digitorum superficialis, it bends your fingers by contracting and bending them back toward itself.
This video (of unknown origin) which we saw Tweeted by the account How Things Work, illustrates the effect using a cadaver limb:
I can't stop staring at it.
This is how you flex your fingers pic.twitter.com/BACT0bub5q
- How Things Work (@ThingsWork) February 16, 2017
- Fresh photographs of Milky Way’s black hole Sgr A* reveal strong, twisted magnetic field similar to M87*
- 8 Lesser-known places to explore in Himachal Pradesh
- Markets end FY24 on buoyant note amid positive global cues
- SRM Contractors IPO allotment – How to check allotment, GMP, listing date and more
- Rupee falls 6 paise to settle at 83.39 against US dollar