Case 11: EMG and MRI

The nerve conduction study was normal. EMG showed reduced insertional activity in the vastus medialis and occasional myopathic units. As there only mild weakness of  knee extension (quadriceps) on manual strength testing, , EMG was done on rectus femoris (RF) , which was normal.  Reduced insertional activity is a non-specific finding that could happen in end stage neurogenic and myopathic conditions. And implies end stage muscle, such as replacement of muscular tissue with fatty cells.

The involvement of quadriceps (atrophy and fat replacement) with sparing of RF is also noted in the MRI studies (right column). Click here for further workup, diagnosis.