A catheter for a morphological duct is disclosed, comprising an inflatable sleeve surrounding the distal end of said catheter and connected to the proximal end of said catheter by at least one inflating conduit which can be connected to an inflating device and said inflatable sleeve may take on either a deflated state in which it is applied against said distal end of said catheter, or an inflated state in which it is applied by its external wall against the internal wall of said morphological duct, then forming an annular space between its internal wall and said distal end of said catheter.