What is a characteristic symptom of posterior interosseous syndrome?

• A. Weakness of thumb abduction
• B. Bilateral wrist pain
• C. Pain increased with middle finger extension
• D. Loss of sensation in the palm

Answer: (C)

Posterior interosseous syndrome is often characterized by weakness or inability to extend the fingers, particularly affecting the extensor digitorum muscle, which is responsible for extending the fingers at the metacarpophalangeal joints. The pain associated with this syndrome can indeed be aggravated by activities that involve the extension of the middle finger. Thus, the symptom of pain that increases with middle finger extension aligns with the typical presentation of posterior interosseous syndrome.

This syndrome results from compression of the posterior interosseous nerve, a branch of the radial nerve, and this specific symptom is a hallmark that helps in diagnosing the condition. During clinical evaluation, patients often report a loss of strength in finger extension, which is significant in distinguishing this syndrome from other conditions affecting the wrist and hand.