A catheter member (1) for interacting with a circumferential tissue structure (10) includes an elongate primary catheter (70) which has an inner lumen (80) and which extends along a longitudinal axis (90) and has a distal end portion (100), first (120) and second (130) elongate secondary catheters each comprising a distal end portion (140, 150) and an inner lumen (160, 170), and each to be disposed in the inner lumen (80) of the primary catheter (70) to be moveable relatively thereto and exposable from the distal end portion thereof, and a first flexing mechanism (191) to provide the distal end portion (140, 150) of the first (120) and/or second (130) secondary catheter with a tendency to assume a first secondary bent shape, wherein the distal end portion of one or both of the first and second secondary catheters is provided so as to be able to be flexed by the first flexing mechanism to form an arm portion (126, 136) substantially transverse to the direction of the longitudinal axis (90) of the primary catheter (70) so as to assume the first secondary bent shape, when being exposed from the distal end portion (100) of the primary catheter.
