Advanced Radial Nerve Quiz

Q1. A fracture through the midshaft of the humerus places the radial nerve at particular risk because of its relationship to which structure?

• Medial epicondylar groove
• Intertubercular sulcus
• Coronoid fossa
• Radial groove

Q2. Why may elbow extension be preserved or only weakened rather than completely lost after a radial nerve injury in the radial groove?

• Some triceps branches arise proximal to the lesion
• The triceps does not contribute to elbow extension
• The median nerve supplies the entire triceps
• The ulnar nerve replaces the radial nerve at the elbow

Q3. Which motor deficit is particularly characteristic of a radial nerve lesion at the humeral shaft?

• Loss of finger abduction
• Loss of thumb opposition
• Loss or severe weakness of wrist extension
• Loss of forearm pronation

Q4. Which cutaneous area is commonly tested for radial nerve sensation because it has relatively little overlap from neighboring nerves?

• Palmar surface of the index fingertip
• Thenar eminence
• Dorsal first web space
• Tip of the little finger

Q5. A lesion limited to the posterior interosseous nerve would most characteristically produce which finding?

• Loss of elbow flexion with lateral forearm numbness
• Finger and thumb extension weakness without cutaneous sensory loss
• Thenar paralysis with numbness of the index finger
• Loss of finger abduction with numbness of the little finger

Q6. Which structure is a common site of compression of the deep branch of the radial nerve as it enters the supinator?

• Guyon canal
• Flexor retinaculum
• Arcade of Frohse
• Cubital tunnel

Q7. A radial nerve lesion in the axilla would be expected to cause a more extensive deficit than a lesion in the radial groove because which additional function may be severely affected?

• Elbow extension
• Forearm pronation
• Finger adduction
• Thumb opposition

Q8. Which reflex primarily assesses the C7 spinal level through the radial nerve?

• Achilles reflex
• Triceps tendon reflex
• Patellar reflex
• Biceps tendon reflex

Q9. Why does wrist drop reduce the effectiveness of finger flexion and grip?

• Wrist flexion places the long finger flexors at a mechanical disadvantage
• Wrist drop prevents blood from reaching the fingers
• The radial nerve directly supplies all finger flexors
• The flexor tendons rupture whenever wrist extension is lost

Q10. Which description best summarizes the radial nerve?

• A lateral cord nerve supplying only biceps brachii and brachialis
• A purely sensory nerve confined to the dorsum of the hand
• A C5 to T1 posterior cord nerve supplying major extensor muscles and sensory territories of the upper limb
• A medial cord nerve supplying the forearm flexors and intrinsic hand muscles