A 23-year-old male with insidious pain on the radial side of the palm and paresthesias in the thumb, index, and middle finger, worsened by activity such as tennis, is most likely diagnosed with which condition?

• A. Anterior interosseous nerve entrapment
• B. Radial tunnel syndrome
• C. Pronator teres syndrome
• D. Posterior interosseous nerve entrapment

Answer: (C)

Compression of the median nerve at the elbow, specifically under the pronator teres muscle, is the scenario here. When the median nerve is irritated in this location, you get insidious forearm pain and sensory changes in its distribution to the thumb, index, and middle fingers, which can extend to the palm. Repetitive forearm pronation and elbow flexion—like playing tennis—can worsen the pressure under the pronator teres and bring on the symptoms.

Why the others don’t fit as well: anterior interosseous nerve entrapment affects only motor fibers to deep forearm muscles, so there would be weakness (like a pinch sign) without the sensory symptoms in the digits. posterior interosseous nerve entrapment and radial tunnel syndrome involve the radial nerve and typically produce motor weakness of finger extension or dorsal forearm pain, not the median nerve sensory pattern in the palm and the thumb–middle finger distribution.