Tubal cannulation is a procedure where a thin catheter is advanced through the proximal portion (the part closest to the uterus) of the Fallopian tube to examine and possibly restore tubal patency. The catheter is guided by fluoroscopy (real-time X-ray imaging) or hysteroscopy (inspection of the uterine cavity by endoscopy, to the location of the Fallopian tube opening into the uterine cavity. Then it passes through the adjoining, or proximal, part of the Fallopian tube. An inflatable balloon on the tip of the catheter then may be used to open up the blockage of the tube.