Advanced Abductor Pollicis Longus Quiz

Q1. Abductor pollicis longus is commonly involved with extensor pollicis brevis in which clinical condition?

• Carpal tunnel syndrome
• Cubital tunnel syndrome
• Pronator syndrome
• De Quervain tenosynovitis

Q2. Why can anatomical variation within the first dorsal compartment affect treatment of De Quervain tenosynovitis?

• The tendon normally passes through the carpal tunnel
• Multiple tendon slips and separate subcompartments may be present
• The muscle is always absent in affected patients
• The tendon normally joins the ulnar nerve

Q3. A lesion of the posterior interosseous nerve could weaken abductor pollicis longus while generally sparing which type of function?

• Finger extension
• Thumb abduction
• Thumb extension
• Cutaneous sensation

Q4. Which artery crosses the floor of the anatomical snuffbox deep to the tendons forming its boundaries?

• Radial artery
• Brachial artery
• Ulnar artery
• Anterior interosseous artery

Q5. Which bones contribute to the floor of the anatomical snuffbox beneath the abductor pollicis longus region?

• Pisiform and hamate
• Scaphoid and trapezium
• Capitate and hamate
• Lunate and triquetrum

Q6. What is a common anatomical variation of the distal abductor pollicis longus tendon?

• Division into multiple tendon slips
• Complete absence of a distal tendon in all adults
• Insertion exclusively on the distal phalanx
• Obligatory fusion with flexor pollicis longus

Q7. Why can abductor pollicis longus influence the position of the first metacarpal directly?

• It inserts directly on the base of the first metacarpal
• It attaches only to the flexor retinaculum
• It inserts directly into the scaphoid
• It inserts only into the distal phalanx

Q8. Which finding would most directly indicate impaired abductor pollicis longus function?

• Loss of elbow flexion
• Loss of finger adduction
• Weakness of thumb abduction at the carpometacarpal joint
• Loss of thumb interphalangeal flexion

Q9. Which feature distinguishes abductor pollicis longus from extensor pollicis brevis despite their shared first dorsal compartment?

• Abductor pollicis longus passes through the carpal tunnel
• Abductor pollicis longus inserts primarily on the distal phalanx
• Abductor pollicis longus inserts primarily on the first metacarpal
• Abductor pollicis longus is supplied by the median nerve

Q10. Which description best summarizes the anatomy of abductor pollicis longus?

• It is a deep posterior forearm muscle supplied by the posterior interosseous nerve that inserts on the first metacarpal and abducts the thumb
• It is a deep anterior forearm muscle supplied by the anterior interosseous nerve that inserts on the distal phalanx
• It is an intrinsic thenar muscle supplied by the recurrent median nerve
• It is a superficial anterior forearm muscle supplied by the median nerve that flexes the thumb