Trigger finger is caused by irritation, inflammation, and swelling of the tendon or its surrounding sheath in the affected finger or thumb. This inflammation makes it difficult for the tendon to smoothly glide through the sheath, often resulting in a nodule forming on the tendon that catches on the pulley system (particularly the A1 pulley), causing the finger to lock or catch when bent
. Key causes and risk factors include:
- Repetitive or forceful use of the fingers or thumb , such as gripping, grasping, or using vibrating tools, which can irritate the tendon sheath
- Age and gender : More common in people aged 40 to 60 and more frequent in women than men
- Medical conditions : Diabetes, rheumatoid arthritis, gout, hypothyroidism, amyloidosis, carpal tunnel syndrome, and Dupuytren's contracture increase the risk
- Previous hand injury may predispose to trigger finger
- The exact reason why the swelling starts is often unknown, and in over half of cases, no specific cause is identified
In summary, trigger finger results from inflammation and narrowing of the tendon sheath, often linked to repetitive strain, certain health conditions, and sometimes unknown causes, leading to difficulty in tendon movement and finger locking.
