What is a notable feature of anterior interosseous syndrome?

• A. Sensory changes in the hand
• B. Weakness of the pronator quadratus
• C. Pain radiating to the elbow
• D. Increased range of motion

Answer: (B)

A notable feature of anterior interosseous syndrome is the weakness of the pronator quadratus muscle. This condition arises from compression of the anterior interosseous nerve, a branch of the median nerve that innervates specific muscles in the forearm. The primary impact of this syndrome is on the motor function rather than sensory perception.

In particular, the pronator quadratus is crucial for facilitating forearm pronation. Therefore, weakness in this muscle leads to difficulty with pronation and fine finger movements, particularly as it affects the flexor pollicis longus and the flexor digitorum profundus to the index finger as well.

While sensory changes in the hand, pain radiating to the elbow, and increased range of motion might be associated with other conditions, they do not characterize anterior interosseous syndrome itself. This syndrome specifically highlights motor deficits in the affected muscles.