De Quervain’s Tenovaginitis
Tenovaginitis of the abductor pollicis longus and extensor pollicis brevis tendons. This is a common and well recognised condition characterised by pain over the styloid process of the radius and a palpable nodule in the course of the abductor pollicis longus and extensor pollicis brevis tendons.
The precise cause is unknown – but excessive friction from overuse may be a contributing factor. The condition is possibly analogous to that other common form of tenovaginitis ‘trigger’ finger.
Digital Tenovaginits Stenosans
(‘Trigger’ finger; snapping finger – common RSI) In this rather common condition thickening and constriction of the mouth of a fibrous digital sheath interfere with the free gliding of the contained flexor tendons.
Rupture or Severance of the Tendons in the Hand
Most tendon divisions in the hand are caused by cuts with sharp objects such as glass or knives. Certain tendons are prone to rupture; thus the extensor tendon of a finger is easily torn from its insertion into the distal phalanx by sudden forced flexion of the finger.