The distal tendons of which muscles form the anatomical snuff box?

• A. Abductor pollicis longus, Extensor pollicis longus, and Extensor pollicis brevis
• B. Abductor pollicis longus, Flexor pollicis longus, and Extensor pollicis longus
• C. Extensor pollicis longus, Extensor pollicis brevis, and Flexor pollicis longus
• D. Abductor pollicis brevis, Extensor pollicis longus, and Extensor pollicis brevis

Answer: (A)

The anatomical snuff box is defined by the tendons on the dorsum of the hand at the base of the thumb. Its borders are formed by the distal tendons of three thumb-related muscles: Abductor pollicis longus and Extensor pollicis brevis lie on the radial (thumb-side) border, while Extensor pollicis longus forms the ulnar border. These tendons cross to insert around the thumb and create that hollow area you can palpate just distal to the wrist. The other muscles listed don’t form these borders: the flexor pollicis longus lies on the palmar side, and the intrinsic thenar muscle Abductor pollicis brevis doesn’t contribute to the snuff box boundary.