So I apologise for the lightness of postage. BUT I did get a little time to start studying the innards of the hands.
It's really strange drawing the carpals, it looks like a little bag of bones. With a quick Google search though, it's very apparent of their function
"....the main role of the carpus is to facilitate effective positioning of the hand and powerful use of the extensors and flexors of the forearm, but the mobility of individual carpal bones increase the freedom of movements at the wrist."1
I liked these two images too (below), as they are just super clear on where the carpal bones are placed and how the ligaments are entwined. I think it's important to study these ligaments, because it helps you know what's going on underneath when you are drawing, and that makes such a difference, I can't even explain.
Now, further search led me to this image (see below), which I think is a really important thing to note when studying underneath, and knowing how the skin lays out on top. Also, the rest of that page is a GEM! Check it out here. It has a ton of stuff on proportions and range of motion, hella useful for drawing and animation alike.
I also found this really easy to follow video about fingers, thumb and wrist movement
And here are some of my studies from X-rays, skeletons and diagrams
Do you have any cool hand references? Or some cool art? As long as it's hand related, it can be anything at all, just post the links in the comments, or email me, and maybe I'll include it in my next post.