All joints
Joint guide
Thumb IP joint
The hinge at the end of the thumb (only one “finger” joint past the knuckle). It curls and straightens for fine pinch and key pinch.
Diagram
Schematic for orientation — not a substitute for imaging or an in-person exam.
Related anatomy topics
Sources & further reading
We cite major society patient education, NIH institute pages, and MedlinePlus for naming and general joint context. Links open in a new tab; access dates help you judge currency when guidelines update.
- Arthritis of the hand — OrthoInfo — American Academy of Orthopaedic Surgeons(accessed 2026-04-24)
- Hand and wrist anatomy — American Society for Surgery of the Hand(accessed 2026-04-24)
- Hand injuries and disorders — MedlinePlus (U.S. National Library of Medicine)(accessed 2026-04-24)