The vastus muscle flexes the hind leg and runs from stifle to hip, while the gluteal muscles, the large muscles in the hip, extend the femur.
With no clear delineation, it is simply the most distal fibres of the vastus medialis.
The vastus medialis obliquus muscle courses over the anteromedial thigh, attaching along the adductor magnus anterior border and to the quadratus femoris tendon.
Between the adductor magnus and the vastus medialis four muscles are inserted: the iliacus and pectineus above; the adductor brevis and adductor longus below.
It can also result from soft-tissue abnormalities, such as a torn medial patellofemoral ligament, or a weakened vastus medialis obliquus.
The patella is stabilized by the insertion of vastus medialis and the prominence of the anterior femoral condyles, which prevent lateral dislocation during flexion.
It is between the vastus medialis, and the adductors and pectineus.
