A method of selective catheterism of in a network of conduits of an anatomical structure including inserting a flexible distal end of a guide for catheterism through the network of conduits. An appendage is attached on the distal end of the guide, the appendage includes a channel extending along a longitudinal axis of the guide. A catheter is slid along the catheter until a distal face of the catheter surrounding the guide engages a proximal surface of the appendage. A force oriented in a distal direction is exerted with the catheter on the appendage, which disengages the appendage from the distal end of the guide within the network of conduits. Navigation through the network of conduits is continued with the flexible distal end of the guide once the appendage is removed.