Question

Muscles affected in De Quervain tenosynovitis are -

• A. Abductor pollicis longus and extensor pollicis brevis
• B. Adductor pollicis longus and extensor pollicis brevis
• C. Abductor pollicis longus and flexor pollicis brevis
• D. Adductor pollicis longus and flexor pollicis brevis

Hint:

Think of the two tendons in the first dorsal wrist compartment.

Answer 1

The Correct Option is A

Step 1: De Quervain tenosynovitis is a stenosing tenosynovitis affecting the tendons that pass through the first dorsal compartment of the wrist. There is non-inflammatory thickening of the tendons and of the synovial sheath through which they glide.
Step 2: The first dorsal compartment contains exactly two tendons - the abductor pollicis longus (APL) and the extensor pollicis brevis (EPB). Repetitive thumb abduction and extension irritate this sheath, producing pain over the radial styloid and a positive Finkelstein test.
Step 3: Therefore the muscles whose tendons are affected are the abductor pollicis longus and the extensor pollicis brevis, making option a correct.
Step 4: The distractors are wrong because the thumb is abducted by the abductor (not adductor) pollicis longus, and the second tendon is the extensor (not flexor) pollicis brevis. The flexor pollicis brevis and adductor pollicis are intrinsic hand muscles that do not pass through the first dorsal compartment.