Dequervain’s tendinitis occurs when the tendons around the base of the thumb are irritated or constricted
The word “tendinitis” refers to a swelling of the tendons. Thickening of the tendons can cause pain and tenderness along the thumb side of the wrist. This is particularly noticeable when forming a fist, grasping or gripping things, or when turning the wrist.
Two of the main tendons to the thumb pass through a tunnel (or series of pulleys) located on the thumb side of the wrist. Tendons are rope-like structures that attach muscle to bone. Tendons are covered by a slippery thin soft-tissue layer, called synovium. This layer allows the tendons to slide easily through the tunnel. Any thickening of the tendons restrains gliding of the tendons through the sheath. Movement of the thumb may cause pain at the thumb side of the wrist.
DeQuervain’s tendinitis is caused when tendons on the thumb side of the wrist are swollen or irritated. The irritation causes the lining (synovium) around the tendon to swell, which changes the shape of the compartment. This makes it difficult for the tendons to move as they should.
DeQuervain’s tendinitis is most common in middle-aged women. It can be seen in association with pregnancy. It may be found in inflammatory arthritis, such as rheumatoid arthritis. Tendinitis may be aggravated by overuse.