Pathogenesis and treatment of scapholunate (SL) injuries are still under definition in the literature, especially in chronic cases. A two-stage mechanism able to create a chronic injury has been described by several authors. A partial initially asymptomatic injury to the SL ligament can later become symptomatic. The treatment of these injuries is not standardized in the different stages and not always satisfactory. Lack of early diagnosis of this injury can develop a chronic instability leading to degenerative arthritis and SLAC wrist. The aim of this study is to experimentally cut the different parts of the scapholunate ligament and extrinsic ligaments in cadaveric wrists and check the corresponding arthroscopic finding. The SL ligament was evaluated at the beginning of the dissections. Extrinsic ligament tension or laxity was also assessed arthroscopically and by specific tests. A new classification by the European Wrist Arthroscopy Society (EWAS) is proposed to better define the different stages and improve treatment.