Lateral trochlear inclination:  (normal > 11 degrees).
Trochlear facet asymmetry:  (normal > 40%).
Trochlear depth:  (normal > 3 mm).
Patella alta:  (normal < 1.3)
333 N. Commercial Street, Suite 100
Neenah, WI 54956
Radiology Associates of the Fox Valley
For a discussion of patellar instability including a description of patellofemoral measurements, see Diederichs G, Issever AS, Scheffler S. MR imaging of patellar instability: injury patterns and assessment of risk factors. RadioGraphics 2010;30:961-981.