The wrist is the junction between the two forearm bone, the radius and ulna, the carpal bones, and the hand. Their are eight carpal bones- the scaphoid, lunate, triquetrum, pisiform, hamate, capitate, trapezoid and trapezium.
( Picture from American Society for Surgery of the Hand)
The carpal bones join the hand bones called the metacarpals.
There is a complex motion and load transfer across the wrist to enable the hand to do what tasks we require.
Injuries and wear can alter those mechanics of joints, ligaments and other soft tissues.