Advanced Extensor Pollicis Longus Quiz

Q1. A patient cannot actively extend the distal phalanx of the thumb after an injury. Which tendon should be specifically assessed?

• Flexor carpi radialis tendon
• Abductor pollicis longus tendon
• Extensor pollicis brevis tendon
• Extensor pollicis longus tendon

Q2. Extensor pollicis longus tendon rupture is a recognized delayed complication of which injury?

• Isolated clavicle fracture
• Olecranon fracture
• Distal radius fracture
• Proximal humeral fracture

Q3. Why is the extensor pollicis longus tendon particularly vulnerable near Lister's tubercle?

• It changes direction around the tubercle within a confined tendon compartment
• It inserts directly into Lister's tubercle
• It passes through the carpal tunnel with the median nerve
• It crosses the elbow joint immediately before insertion

Q4. Which tendon is commonly used as a donor to restore thumb extension after an irreparable extensor pollicis longus rupture?

• Pronator teres
• Palmaris brevis
• Flexor digitorum profundus to the little finger
• Extensor indicis

Q5. Why can extensor indicis be transferred to replace a ruptured extensor pollicis longus while preserving substantial index finger extension?

• Extensor indicis normally has no role in index extension
• The index finger also receives an extensor digitorum tendon
• Flexor digitorum profundus becomes the main index extensor
• The median nerve directly extends the index finger

Q6. A lesion of the posterior interosseous nerve would directly weaken which action of extensor pollicis longus?

• Adduction of the thumb
• Extension of the thumb, especially at the interphalangeal joint
• Flexion of the thumb at the interphalangeal joint
• Opposition of the thumb

Q7. Why can posterior interosseous nerve palsy weaken extensor pollicis longus without causing cutaneous sensory loss in the hand?

• The radial nerve contains no sensory fibers
• The posterior interosseous nerve is predominantly motor
• Extensor pollicis longus is supplied by the median nerve
• Thumb extension does not require peripheral nerve supply

Q8. During surgical fixation of a distal radius fracture, prominent dorsal hardware near which landmark can endanger the extensor pollicis longus tendon?

• Medial epicondyle
• Radial tuberosity
• Lister's tubercle
• Coronoid process

Q9. A patient retains some extension of the thumb metacarpophalangeal joint but cannot extend the interphalangeal joint. Which isolated tendon injury best explains this pattern?

• Flexor pollicis longus tendon rupture
• Abductor pollicis longus tendon rupture
• Extensor pollicis brevis tendon rupture
• Extensor pollicis longus tendon rupture

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

• It is a superficial anterior forearm muscle supplied by the median nerve that inserts on the proximal phalanx of the thumb
• It is a deep posterior forearm muscle supplied by the posterior interosseous nerve that passes around Lister's tubercle and inserts on the distal phalanx of the thumb
• It is a superficial posterior forearm muscle arising from the lateral epicondyle and inserting on the first metacarpal
• It is an intrinsic thenar muscle supplied by the ulnar nerve that primarily adducts the thumb