Trigger finger (a.k.a. Stenosing tenosynovitis and Historicopous ) is a disorder characterized by the (sometimes painful) catching or locking of a finger, or the thumb. The name is given because of the popping sound made by the affected finger when flexed or extended.

It was first described in 1850, and is thought to affect around 2-3% of adults (10% in diabetics)

Although the disorder is known to be due to malformation of the diameters of a flexor tendon and its retinacular sheath, the exact cause has not yet been identified.

Several causes of trigger finger have been proposed, though the precise etiology has not been elucidated. Understandably, repetitive finger movements and local trauma are possibilities, with such stress and degenerative force also accounting for an increased incidence of trigger finger in the dominant hand. There are reports linking trigger finger to occupations requiring extensive gripping and hand flexion, such as use of shears or hand held tools. This relationship is questionable, however, with studies finding no association between trigger finger and the workplace. In reality the causes of trigger finger are multiple and in each individual often multifactorial.

Source : Curr Rev Musculoskelet Medv.1(2)