When the back of the thumb is painful and stiff, especially for those who do repetitive movements with their hands and wrists, it is often the result of a condition called De Quervain’s tenosynovitis [DE-KWAIR-VAINS TENO-SYNO-VIE-TIS].
De Quervain’s tenosynovitis is also known as De Quervain’s tendinosis, tendonitis, disease, or syndrome. It is also sometimes called “mommy thumb” because it can affect those who care for children.
See What Is the Difference Between Tendonitis, Tendinosis, and Tendinopathy?
Understanding what causes De Quervain’s tenosynovitis—and how it can be treated—is important for those at risk for the condition.
Inflammation in Tendons of the Thumb
Tendons empower movement by connecting bones to muscles. The thumb contains unique tendons that allow it to move independently of the other fingers and perform actions like pinching and gripping.
Most often due to chronic overuse, inflammation can affect the tendons (known as tendonitis) or the synovium, a sheath that lines and protects the tendon (known as tenosynovitis).
See Wrist Tendonitis: An Overview
Two tendons in the thumb—the extensor pollicis brevis and the abductor pollicis longus—extend side-by-side over the back of the thumb. When inflammation occurs in these tendons and/or their synovial sheaths, the tendons can no longer slide easily under the band of fascia that holds them in place, known as the extensor retinaculum.
When this inflammation becomes chronic, De Quervain’s tenosynovitis may be diagnosed.
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Diagnosing Thumb Pain
To determine if thumb pain is caused by De Quervain’s tenosynovitis, physicians will ask about the patient’s history of symptoms, as well as taking into consideration the known risk factors, such as age, sex, history of injury, and repetitive hand activities.
A physical test called the Finkelstein test is used by physicians to detect De Quervain’s tenosynovitis. The test is performed by having patients make a fist with the thumb folded inside the fist, then moving their hand downward, away from the thumb. If this motion triggers pain at the base of the thumb, the condition is indicated.
Ultrasound imaging tests may also be used to detect inflammation or damage in the tendons and sheaths and confirm a diagnosis.
Primary care physicians can usually diagnose and treat De Quervain’s tenosynovitis without the need for specialist consultation. If a surgical procedure is indicated to treat the condition, patients can be referred to an orthopedic surgeon who specializes in the upper extremities.
Knowing more about the specific symptoms and risk factors for De Quervain’s tenosynovitis is a good first step in getting pain relief.