The two muscles affected are the extensor pollicis brevis (EPB) and abductor pollicis longus (APL ... affects the thumb—is a common cause of thumb pain. It affects the flexor tendon that ...

Scar tissue develops within the flexor sheath, decreasing the space available for the tendons. Late direct repair is most commonly performed in the thumb ... the flexor pollicis longus (FPL ...

Research has also explored the spontaneous resolution of pediatric trigger thumb, examining changes in the flexor pollicis longus tendon during this process. A study using ultrasonography found ...