Table 2 Classification of trigger wrist by Al-Qattan et al. [3]

A

Tumor or inflammatory mass that may originate from the median nerve, flexor tendon, or other contents of the carpal tunnel

B

Anomalous muscle crossing the carpal tunnel

C

Tumor within an anomalous muscle crossing the carpal tunnel

D

Partial flexor or extensor tendon injury at the wrist level

E

Mechanical causes such as snapping dislocation of a flexor tendon over the hook of the hamate (may occur after carpal tunnel release), and tendon adhesions between the flexor pollicis longus and other flexor tendons within the carpal tunnel (may occur following surgery within or near the carpal tunnel)