It is shown that the dorsal ganglion arises as a herniation from the dorsal scapholunate ligament. This herniation increases in size (according to La Place's law) owing to the unidirectional pinchcock effect of the mucosal folds of the duct and the pressure of the overlying extensor retinaculum until the distending pressure inside the ganglion equals the overlying tissue pressure. Wrist gangliography, retrograde wrist arthrography, histology and nuclear magnetic resonance were used to prove this conclusively. Bearing the pathogenesis in mind, the best clinical results were obtained by excision of the ganglion with 0.5 cm2 of dorsal scapholunate ligament and closure of the dorsal capsule with a 3/0 Vicryl purse-string suture. Non-surgical sclerotherapy led to severe inflammation and sepsis and a recurrence rate of 45%. Conservative therapy is illogical since the communicating duct remains and synovial fluid from the scapholunate joint will cause a reherniation and recurrence of the ganglion.