Advanced Ulnar Nerve Quiz

Q1. Which motor finding is particularly useful for testing the ulnar nerve in the hand?

• Forearm pronation
• Finger abduction against resistance
• Elbow flexion against resistance
• Thumb opposition

Q2. Froment sign primarily tests weakness of which muscle?

• Opponens pollicis
• Abductor pollicis brevis
• Extensor pollicis longus
• Adductor pollicis

Q3. Which nerve produces the compensatory thumb interphalangeal flexion seen in a positive Froment sign?

• Median nerve through the anterior interosseous nerve
• Axillary nerve
• Musculocutaneous nerve
• Radial nerve through the posterior interosseous nerve

Q4. Why can an ulnar nerve lesion produce clawing of the ring and little fingers?

• Loss of interossei and medial lumbrical function
• Paralysis of all finger flexors
• Loss of the long finger extensors
• Paralysis of pronator teres

Q5. Why may clawing be more pronounced after an ulnar nerve lesion at the wrist than after a lesion at the elbow?

• All finger extensors are paralyzed in the distal lesion
• The distal lesion also paralyzes biceps brachii
• The median nerve is always injured with a proximal lesion
• The medial flexor digitorum profundus remains functional in the distal lesion

Q6. Which finding favors an ulnar nerve lesion at the elbow rather than an isolated lesion within Guyon canal?

• Weakness of the interossei
• Weakness of flexor carpi ulnaris
• Weakness of finger abduction
• Weakness of adductor pollicis

Q7. Why may dorsal ulnar hand sensation be preserved in an isolated lesion within Guyon canal?

• The ulnar nerve has no sensory fibers
• The dorsal cutaneous branch arises proximal to Guyon canal
• The dorsal cutaneous branch arises from the radial nerve
• The dorsum of the hand is supplied only by the median nerve

Q8. A lesion of the ulnar nerve proximal to the medial epicondyle would most directly weaken which combination of actions?

• Shoulder abduction and lateral rotation
• Ulnar deviation during wrist flexion and finger abduction and adduction
• Forearm pronation and thumb opposition
• Elbow extension and wrist extension

Q9. Which sensory region is useful for testing the autonomous cutaneous territory of the ulnar nerve?

• Skin over the deltoid
• Tip of the little finger
• Dorsal first web space
• Tip of the index finger

Q10. Which description best summarizes the ulnar nerve?

• A posterior cord nerve supplying the extensor compartments of the arm and forearm
• A purely sensory nerve confined to the medial side of the arm
• A mainly C8 to T1 medial cord nerve that passes behind the medial epicondyle and supplies important forearm and hand structures
• A C5 to C6 lateral cord nerve supplying the anterior arm