A device which includes a gas insufflation device (1), a first duct (2) for supplying gas to a member insertable (3) in a cavity of an individual. The first duct (2) includes a by-pass (21) for evacuating excess gas towards the exterior. The insertable member (3) has three passages and includes a first mouth (31) at its rear end for coupling the first duct (2) to a passage (32) having an exit mouth (33), a second mouth (34) for coupling an effluent evacuation duct (5) to a passage (35) having an entrance mouth (36), and a third mouth (37) for connecting inflating means (6) of an expandable ring-shaped element (30) with a passage (38) having an exit mouth (39) to the expandable ring-shaped element (30) disposed before the mouths (33, 36).
