BOSTON — Aspiration — just ulnar to Lister’s tubercle — may help protect the extensor pollicis longus from rupturing ... created a 6-forearm cadaveric model with a nondisplaced distal ...

Your forearm anatomy includes 20 muscles, ranging from the extensor carpi radialis longus to the abductor pollicis longus. One of the largest is the brachioradialis, which helps to bend your elbow.

Specifically, it affects the tendons of two muscles called abductor pollicis longus and extensor pollicis brevis. De Quervain tenosynovitis was named after Swiss surgeon Fritz de Quervain.