Anatomy

Each finger has three joints: the MCP knuckle, the PIP middle joint and the DIP fingertip joint. The thumb has two plus its base. What each does, what injures it, and why the middle one is the one to protect.

Your elbow is three joints inside one capsule, where the humerus, ulna and radius meet. Here is what each joint, ligament, tendon and nerve does, why the elbow stiffens so fast, and how much movement you actually need.

Your thumb has 3 bones, 3 joints and 9 muscles, and impairment guides rate it at about 40% of hand function. How it works, what goes wrong where, and which thumb injuries can’t wait.

Your wrist has 8 carpal bones in two rows: scaphoid, lunate, triquetrum, pisiform, then trapezium, trapezoid, capitate, hamate. Here is where each sits, how to find them, and what goes wrong in each part of the wrist.

Thumb, index and middle finger belong to the median nerve, ring and little to the ulnar, the back of the thumb web to the radial. Which fingers go numb is the most useful clue you can bring to an appointment.

Your fingers are moved by tendons from muscles in your forearm: two flexor tendons bend each finger, one extensor mechanism straightens it. Here’s the map, the self-tests, and which tendon matches your symptom.