A device for treating carpal tunnel syndrome of a person's hand, which has a palmar aspect, with thenar and hypothenar regions, and a dorsal aspect opposite the palmar aspect. The cuff has a C-shaped profile in cross section, wherein two ends of the C-shaped profile of the cuff form the cuff opening. The cuff is formed from two or more cuff parts, wherein these cuff parts have a C-shaped profile in cross section and are connected to each other by means of a connection element to form the cuff. The cuff parts are preferably connected to each other, by means of the connection element, in a movable and/or pivotable and also releasable manner, such that the width of the cuff opening can be individually adapted for each patient. This results in simple, efficient and safe treatment and handling of the cuff according to the invention or of the device.