But instead, human hands have a renegade element, a fly in the ointment, a crazy uncle who makes everything complicated. You know why thumbs ruin everything?
Because they operate on an entirely different plane of existence than fingers.
Let’s look at the basic structure of the hand, then examine this whole spatial plane problem. First, of all, hands (like feet) are wedges. They are not flat.
(As you can see in this helpful public domain image I got from wikipedia, verified by my own personal knowledge, thanks to Minerva Durham my incredible anatomy teacher at Parsons!)
The thumb is missing one phalange, the intermediate phalange.
It might be more helpful, however, to think of the thumb as attaching to your hand in a different place than the fingers.
Your thumb and fingers have the same amount of knuckles, three, but the third knuckle of your thumb attaches to the base or heel of your hand instead of at the top of the palm!
It’s like we’re creepy mutants or something.
Your fingers splay out from the top of your palm in a group; your thumb projects from the bottom, on a much larger axis of rotation.
Your thumb rotates from the crazy midden heap of your carpal bones, where things are much more dynamic than at the top of your palm.
So your fingers travel in a pack, while your thumb has its own adventures. A good way to understand this is to draw broad arrows on your fingernails, as shown in the drawings, and observe the difference in the way your thumb points for a few days.
A great way to understand the limited rotational arc of the fingers is to visualise a pack of french fries.
Seeing the hand as a wedge is also important for understanding how the hand attaches to the wrist.
Basically you have a wedge of meat and bone, your hand, pivoting on the junk pile of carpal bones, which are cupped into the ends of your radius and ulna. Your hand doesn’t join your wrist- it pivots on a ball of bones which attaches to your wrist. BJD dolls provide a fabulous reference for this. If you want to draw some awesome wrists, get yourself a BJD doll arm and practise drawing it from every possible angle.
Of course, the best way to draw great hands is to draw bad hands for as long as it takes.
At Parsons I was notorious for choosing the cruelest, harshest, most obsessive teachers and doing whatever awful things they demanded with glee. One of my favorite teachers insisted we spend two entire weeks drawing nothing but hands, and then two weeks doing nothing but feet. I was thrilled, and everyone else was miserable.
I wanted the confidence and power of being able to draw hands as accurately as I drew figures, so that I would never be limited in the poses I could draw.
It was really, really hard, and it was worth it. I can’t recommend it enough, taking the time to learn to draw hands really well.