The structures the rest of the library refers to. Plain-language first; use the strip below for optional clinical names.
For hinge-by-hinge context (MCP, PIP, DIP, wrist, thumb base), see the hand joints guide with diagrams and related anatomy links.
Each hand has 27 bones: 8 wrist (carpal) bones, 5 long hand bones, and 14 finger bones. They line up like a stack of building blocks that lets the hand grip, pinch, and rotate.
Tendons are tough cords that connect muscles in the forearm to the bones of the hand. They glide through tunnels (sheaths) every time you bend or straighten a finger.
Three main nerves run from the neck to the hand: median, ulnar, and radial. They carry feeling and movement signals; pressure on any of them can cause numbness, tingling, or weakness.
Each finger has three joints: the big knuckle, middle joint, and tip joint. The thumb has a saddle joint at its base that lets it move in many directions.
Hand movement comes from two muscle groups: long muscles in the forearm that pull on tendons, and small muscles inside the hand itself ('intrinsics') that fine-tune finger position and pinch.
The wrist is two rows of small bones plus the ends of the forearm bones (radius and ulna). Strong ligaments link them so the wrist can bend, extend, and tilt while still bearing load.
Two main arteries — the radial (thumb side) and ulnar (little-finger side) — feed the hand. They join in two arches in the palm so most fingers stay supplied even if one route is blocked.
Palm skin is thicker and anchored down so it doesn't slide while gripping. Underneath sits a tough fibrous layer (the palmar fascia) that protects deeper structures and can become diseased in conditions like Dupuytren's.
