De Quervain’s tenosynovitis

De Quervain’s tenosynovitis is a condition that effects two tendons that run from the back of the thumb down the side of the wrist. De Quervain’s tenosynovitis happens when these tendons are swollen and irritated. Swelling of the tendons and the tendon sheath (a tunnel-like structure that the tendons travel through at the wrist) can cause pain and tenderness along the thumb side of the wrist.