Anatomical basis of the role of vastus medialis muscle in femoro-patellar degenerative arthropathy.

In order to evaluate the femoro-patellar syndrome, more especially to better define the vastus medialis/vastus lateralis imbalance, we performed 44 anterior thigh region examinations in dissecting room subjects. Vastus medialis morphological aspect was always found regular without definite separation. One the other hand we found two innervation possibilities: either only one nerve pedicle from femoral nerve, associated with cartilage degeneration (arthrosis) located on the patella lateral facet, or two pedicles from femoral nerve, associated with either no arthrosis, or diffuse cartilage degeneration. The innervation mode seems to be determinant to explain the two functions of vastus medialis (knee extension and patellar alignment).