Patellofemoral joint is an integral component of complicated structure of knee, in its crucial role is involved in the disposition of mechanical forces during move so it is a necessary element for the proper functionality and stability of lower limb. Building front compartment of the knee creates protective bumper for an indirect trauma to deeper structures, often this trauma leads to dysfunction of the lower limb extensor mechanism. Because of the long arms of the lever consisting of the thigh and crus, forces exceeding the strength of soft tissues predispose joint to injuries..Secondary to trauma chronic degenerative changes, or chronic instability may occur.In practice, an orthopaedist often has to deal with knee injuries, including patella fractures and disability of extensor mechanism. Quick diagnosis and treatment is crucial to restore the efficiency of gait, decrease pain and for exploration of the characteristics of the injury. On ER, as well as in clinic, therapist has a choice of several imaging techniques in order to search for a proper diagnosis. This article focuses on description of these methods, as well of their values in recognizing specific pathology.