Unleash Your Potential with the 450 Formula Upper Extremity Practice Exam 2026 – Flex, Prep, and Ace It!

De Quervain's tenosynovitis is a stenosing problem of the first dorsal wrist compartment, where the abductor pollicis longus and extensor pollicis brevis tendons glide. When the sheath around these tendons becomes inflamed or thickened, thumb movements—especially abduction and extension—tendon pain and tenderness at the radial-dorsal wrist. The other tendons listed are not in this compartment: the flexor pollicis longus is a palmar-side flexor, the extensor pollicis longus runs in a different (third) dorsal compartment, and the extensor carpi radialis brevis is in the second dorsal compartment. So the tendinopathy involves the two tendons contained in the first dorsal compartment: abductor pollicis longus and extensor pollicis brevis.