De Quervain’s tendinosis occurs when the tendons around the base of the thumb are irritated or constricted. The word “tendinosis” refers to a swelling of the tendons. Swelling of the tendons, and the tendon sheath, can cause pain and tenderness along the thumb side of the wrist. This is particularly noticeable when forming a fist, grasping or gripping something, or when turning the wrist.
