Flexor tendon injury. Flexor tendons run from the arm to the wrist, palm, and fingers. They help you grasp things, bend your fingers and thumb, and make a fist.

De Quervain tenosynovitis is pain and swelling in the tendons around your thumb. Specifically, it affects the tendons of two muscles called abductor pollicis longus and extensor pollicis brevis ...

My doctor, who had me make a painful fist, said that I might have something called De Quervain’s Tendinosis, which affects tendons on the thumb side of the wrist and is caused by chronic overuse ...