Neuromuscular diseases are so alike in symptoms that these should be differentiated accurately by clinical symptoms, physical findings, and electromyographic findings.

This paper reports each case of Scapulo-peroneal Dystrophy (Case 1) and Peroneal Muscular Atrophy (Case 2).

Case 1 is described of muscle weakness and wasting of scapuloperoneal distribution with an onset in middle life and a relatively benign progression. Facial weakness was not noted, but hypertrophied extensor digitorum brevis was a prominant feature. Serum CPK was increased. Nerve conduction study was norma, but electromyographic study demonstrated myopathic changes.

Case 2 is also described of muscle weakness and wasting of peroneal distribution with an onset in late life with progression. Initial complaints was a frequent ankle sprain. This showed pes cavus deformities, slap-footed gait, and sensory disturbance. Nerve conduction and electromyographic studies indicated peripheral neuropathies and anterior horn cell involvement.