This is a case report of a fifty-nine-year-old rheumatoid arthritic woman who developed lack in finger extension bilaterally. These deficits had two completely different aetiologies, Posterior Interosseous Nerve (PIN) Syndrome and extensor tendon rupture. No previous report in the literature has used elbow arthrography as a diagnostic tool in a patient with PIN Syndrome. Elbow arthrography confirmed the abnormality at this joint and aided in appropriate management.