Adduction of thumb occurs at:
C i.e. Carpometacarpal joint 1st carpometacarpal joint (cmj) is the only cmj with seperate joint cavity so the movements are much free. Flexion- extension (in the plane of palm), adduction - abduction (at right angles to the plane of palm), opposition & circumduction, movements of thumbQ take place at 1st CM Joint.
Inter carpal joint
MCP joint
Carpometacarpal joint
Inter phalangeal joint