A medical instrument for intraluminal insertions, comprising: - a main tubular cannulation body (9) with a tubular wall provided with one or more side openings (13-16); - a main catheter (7) crossed by a central channel (6) and intended to be inserted in the main channel of the lumen (18) to be cannulated; - one or more secondary catheters (2-5) passing through respective side openings (13-16) of said tubular wall; - means for inserting and guiding said main tubular body (9) into the lumen (18) to be cannulated, with a release device of the main tubular body (9) provided with a conical tip (1) distally associated with said main catheter (7) and provided with an axial passage coaxial with said central channel (6) in order to facilitate the insertion of said release device into the lumen (18) and a tubular containment casing (8) peripherally placed and coaxially to said main tubular body (9) in order to define an annular chamber (30) adapted to receive at least partially said one or more secondary catheters (2-5).L'invention concerne un instrument médical pour insertions intraluminales, comprenant : - un corps de canulation tubulaire principal (9) avec une paroi tubulaire pourvue d'une ou de plusieurs ouvertures latérales (13-16) ; - un cathéter principal (7) traversé par un canal central (6) et destiné à être inséré dans le canal principal de la lumière (18) à canuler ; - un ou plusieurs cathéters secondaires (2-5) passant à travers des ouvertures latérales respectives (13-16) de ladite paroi tubulaire ; - des moyens d'insertion et de guidage dudit corps tubulaire principal (9) dans la lumière (18) à canuler, avec un dispositif de libération du corps tubulaire principal (9) pourvu d'une pointe conique (1) associée de manière distale audit cathéter principal (7) et pourvu d'un passage axial coaxial audit canal central (6) afin de faciliter l'insertion dudit dispositif de libération dans la lumière (18) et un boîtier de confinement tubulaire (8) placé de manière périph