What Is De Quervain’s Tendinosis?

De Quervain’s Tendinosis occurs when the tendons around the base of the thumb are irritated. Tendinosis refers to swelling of the tendons. Swelling of the tendons or tendon sheath can cause tenderness along the thumb side of the wrist. This is very noticeable when forming a fist, grasping, gripping or even turning the wrist.