The MPFL is indeed the Medial Patello-femoral ligament. It is one of the main components of the medial retinaculum. I think however what you are thinking of is the Patellar Tendon which runs down the middle of your leg and is what your patella sits in. The MPFL goes from the medial side of your patella to an area near where the MCL attaches. It serves to provide stability for the patella and prevent lateral movement.
If you need any other info about the MPFL, let me know as I have had a repair and 2 reconstructions to this little ligament.