Trigger finger is a condition in which one of your fingers gets stuck in a bent position. Your finger may bend or straighten with a snap — like a trigger being pulled and released.
Trigger finger is also known as stenosing tenosynovitis (stuh-NO-sing ten-o-sin-o-VIE-tis). It occurs when inflammation narrows the space within the sheath that surrounds the tendon in the affected finger. If trigger finger is severe, your finger may become locked in a bent position.