A medical tracking system, comprising: a catheter configured to be inserted into, and moved around in, blood vessels of a body-part of a living subject, and comprising a flexible shaft having a deflectable distal end, and a location tracking transducer in the distal end, the location tracking transducer being configured to output a signal that is indicative of a location of the transducer in the body-part; a tracking subsystem configured to track locations of the distal end of the catheter over time responsively to the signal; a display; and processing circuitry configured to: add the tracked locations of the distal end to a movement log; and wherein the processing circuitry is further configured to render to the display an image of at least part of the body-part of the living subject with a representation of a length of the shaft of the catheter in at least one blood vessel of the blood vessels of the body-part, with respective positions along the length of the shaft being located in the image responsively to respective ones of the tracked locations from the movement log; and characterised in that, responsively to the distal end of the catheter being retracted in the at least one blood vessel with respect to at least one tracked location of the tracked locations included in the movement log, the processing circuitry is configured to: remove the at least one tracked location from the movement log yielding an amended movement log; and render the representation of the length of the shaft according to the amended movement log. a catheter configured to be inserted into, and moved around in, blood vessels of a body-part of a living subject, and comprising a flexible shaft having a deflectable distal end, and a location tracking transducer in the distal end, the location tracking transducer being configured to output a signal that is indicative of a location of the transducer in the body-part; a tracking subsystem configured to track locations of the distal end of the catheter over time responsively to the signal; a display; and processing circuitry configured to: add the tracked locations of the distal end to a movement log; and wherein the processing circuitry is further configured to render to the display an image of at least part of the body-part of the living subject with a representation of a length of the shaft of the catheter in at least one blood vessel of the blood vessels of the body-part, with respective positions along the length of the shaft being located in the image responsively to respective ones of the tracked locations from the movement log; and characterised in that, responsively to the distal end of the catheter being retracted in the at least one blood vessel with respect to at least one tracked location of the tracked locations included in the movement log, the processing circuitry is configured to: remove the at least one tracked location from the movement log yielding an amended movement log; and render the representation of the length of the shaft according to the amended movement log. add the tracked locations of the distal end to a movement log; and wherein the processing circuitry is further configured to render to the display an image of at least part of the body-part of the living subject with a representation of a length of the shaft of the catheter in at least one blood vessel of the blood vessels of the body-part, with respective positions along the length of the shaft being located in the image responsively to respective ones of the tracked locations from the movement log; and characterised in that, responsively to the distal end of the catheter being retracted in the at least one blood vessel with respect to at least one tracked location of the tracked locations included in the movement log, the processing circuitry is configured to: remove the at least one tracked location from the movement log yielding an amended movement log; and render the representation of the length of the shaft according to the amended movement log.