trigger finger
noun [ C or U ] uk/ˈtrɪɡ.ə ˌfɪŋ.ɡər/ us/ˈtrɪɡ.ɚ ˌfɪŋ.ɡɚ/
扣扳机的手指
the finger that someone uses to shoot a gun
medical specialized扳机指（手指弯曲后难以伸直的病症）
a disorder of the tendon of a finger that makes it difficult to straighten the finger once it is bent
If a trigger finger is left untreated, the finger may become permanently bent. 如果扳机指不作治疗的话，手指可能会永久弯曲。