For some unknown reason, I was contemplating my knuckles (as opposed to my navel) today and I began to wonder which of the several finger joints were properly called knuckles. When a naughty schoolboy is rapped on the knuckles with a ruler, I’ve always assumed that to refer to the joint between the metacarpals and the proximal phalanges (the bumps between the back of your hand and the fingers themselves). Same thing for scraped knuckles from bicycle wrecks. On the other hand (pun intended), knuckle dragging seems to refer more to the joint between the proximal and middle phalanges, as does rapping on a door with your knuckles and being unable to remove a ring because your knuckles are swollen. So, which is it? And if the answer is both of them, why the multiple usage? I mean, all the other joints have specific and unique names (don’t they?), so why the “one size fits all” nomenclature for finger joints?
Perhaps most simply, a knuckle (or, perhaps more correctly, a knuckle joint) is any joint which involves a phalanx bone. So, the joints between individual phalanges, as well as the joints between phalanges and metacarpals (or even metatarsals) are all knuckles.
So on each hand I have 3 knuckles for each finger? Does my thumb have 1 or two knuckles? Or three (what’s that funky almost wrist bone at the bottom of the thumb?)?
To sum up, on each hand, do I have:
a) 4 knuckles
b) 5 knuckles
c) 8 knuckles
d) 9 knuckles
e) 10 knuckles
f) 12 knuckles
g) 13 knuckles
h) 14 knuckles
i) 15 knuckles
I think I’ve got all combinations not involving some sort of amputation or other surgery.
Be thankful you don’t speak Spanish, where dedos can mean either fingers or toes.
(An amusing fact in conjunction with the translation formerly used for the slogan of Kentucky Fried Chicken here, Como chuparse sus dedos, which can mean either “So that you suck your fingers” and “So that you suck your toes.”)
Oh, and in my considered opinion each hand has 14 knuckles, two for the thumb and three for each of the other fingers.
You (should) have 2 knuckles for digit I (aka “your thumb”), and 3 each for digits II through V, for a total of 14 per hand (as Colibri has already calculated). Same goes for your toes, though your pinkey toe knuckles can be difficult to notice because the phalanges are so small. Digit I of the hand (aka “your thumb”) is made up of a detached metacarpal and two phalanges, whereas each of the other fingers is composed of three phalanges attached to a metacarpal (where metacarpals II - V articulate at the wrist with each other and with the carpals).
Useless trivia: the phalanges which make up the tips of your fingers (toes) are called the “ungual phalanges”. This is where Ungulates (aka “hoofed mammals”) get their name - they stand on their tippy-toes.
Sure, make it sound all reasonable and everything. I still think the different knuckles should have different names. Something like distuckles, miduckles, & proxuckles, maybe. Now all I have to do is write my own anatomy text, get it published, and sell the idea to medical schools around the world. Anybody want to help?
