[Computed tomographic study of the anatomical modifications of the wrist brought about by section of the anterior annular ligament].

The authors have analysed the action of sectioning the transverse carpal ligament by computerised tomography in 19 patients (22 wrists) with carpal tunnel syndrome. Three cuts were studied-proximal, middle and distal, the wrist being either straight, flexed or extended. The study was done pre-operatively and three months after division of the ligament. The study demonstrated the reconstruction of a new ligament which was more lax and expanded anteriorly, despite the fact that the patient wore a plaster cast for two weeks after operation, the wrist being maintained straight. The calibre of the carpal tunnel showed an increase of between 7 p. 100 and 44 p. 100 after the operation and this increase was not related to any alteration in bone topography, which was unchanged. Thus, the role of the ligament in the permanency of shape of the anterior concavity of the wrist skeleton is questionable. The flexor tendons could expand anteriorly, thanks to the laxity of the new ligament.