Prior to continuing, please develop a differential diagnosis and list each diagnosis in order of likelihood. The patient denies neck or shoulder pain and denies symptoms in any of the other limbs. He denies any other medical problems and takes no regular medications. If necessary, please revise your differential diagnosis based on the additional clinical history. The right first dorsal interosseous muscle is markedly atrophied.
Muscle tone is normal.
Sensation is intact to pinprick and 2 point discrimination throughout the upper limbs. Plantar responses are downgoing. At this point, review your differential diagnosis and revise as appropriate. Determine a final working differential diagnosis from which to design yourelectrodiagnostic study. Formulate your approach to the electrodiagnostic study.