Part II · Anatomy · Chapter 18 of 31

Anatomy VI: Arms and hands

Hands are as expressive as faces and just as feared. Treat the hand as a box-shaped palm with a wedge-shaped thumb and four tapering fingers — and remember that the forearm twists to turn it.

The arm

The upper arm is roughly cylindrical, flattened front to back. The forearm is wider at the elbow, narrowing and flattening towards the wrist. When the palm faces down, the radius crosses over the ulna and the forearm's muscles spiral; when the palm faces up they run parallel.

The hand

The palm is about as long as the middle finger. The knuckles do not form a straight line but an arc — the index and middle knuckles are highest, the little finger's lowest. Fingers have three bones each; the thumb has two plus a long metacarpal that sits much lower than the others, near the wrist.

Each finger tapers and bends in a curve, and when the fingers close they all point towards the base of the thumb. Draw the gesture of the hand first — the big curve from wrist to fingertips — then block it with boxes.

Reference table

Part	Bones	Note
Upper arm	Humerus	Deltoid at the top, biceps in front, triceps behind
Forearm	Radius, ulna	Radius turns around the ulna
Wrist	8 carpals	Moves the hand as a block
Palm	5 metacarpals	Slightly arched, not flat
Fingers	3 phalanges each	Joints line up on curves
Thumb	2 phalanges + metacarpal	Swings across the palm; very mobile