Median nerve injury vs Ulnar and radial nerve injuries
How to tell Median nerve injury and Ulnar and radial nerve injuries apart when a board question makes them look alike.
Median is thenar/lateral digits; ulnar is interossei/medial digits; radial is wrist extension/wrist drop.
Side by side
Median nerve injury causes thenar weakness, carpal tunnel sensory symptoms in lateral 3.5 digits, and ape hand or hand of benediction depending lesion.
Ulnar injury causes interossei weakness and medial hand sensory loss; radial injury causes wrist drop and dorsal hand sensory changes.
Median nerve injury causes thenar weakness, carpal tunnel sensory symptoms in lateral 3.5 digits, and ape hand or hand of benediction depending lesion.
Ulnar injury causes interossei weakness and medial hand sensory loss; radial injury causes wrist drop and dorsal hand sensory changes.
The repair move
Before naming the answer, force the stem through the separator: Median is thenar/lateral digits; ulnar is interossei/medial digits; radial is wrist extension/wrist drop.
Try a free question
CoreA 45-year-old typist has 6 months of nocturnal hand pain, numbness in the thumb, index, middle, and radial half of the ring finger, and weakness of thumb opposition with thenar atrophy. Tinel sign at the wrist is positive. Which nerve is compressed, and at which anatomic site?
Show answer and explanation
Answer: A. Median nerve at the wrist (carpal tunnel). Median nerve at the wrist is compressed in carpal tunnel syndrome (beneath the transverse carpal ligament). Risk factors: repetitive wrist activity, pregnancy, diabetes, hypothyroidism, rheumatoid arthritis. Features: sensory loss in lateral 3.5 digits (thumb, index, middle, radial half of ring), nocturnal pain, thenar atrophy and weakness of opposition. Positive Tinel and Phalen signs. Treat with wrist splint, NSAIDs, corticosteroid injection, and carpal tunnel release surgery for refractory cases.
Why the other choices are tempting
- B. Ulnar nerve at cubital tunnel produces medial 1.5 digit sensory loss (little finger, ulnar half of ring) and interossei weakness (claw hand for medial digits).
- C. Radial nerve at radial groove (humerus mid-shaft fracture, Saturday night palsy) causes wrist drop and dorsal hand sensory loss.
- D. Median nerve at elbow (pronator teres syndrome) affects pronation in addition to median distribution but is less common than carpal tunnel.
- E. Long thoracic nerve injury causes serratus anterior weakness (winged scapula).
Flashcards
Tap a card to flip it.
What clue supports Median nerve injury?
Choose Median nerve injury when the stem gives this pattern: Median nerve injury causes thenar weakness, carpal tunnel sensory symptoms in lateral 3.5 digits, and ape hand or hand of benediction depending lesion.
What clue supports Ulnar and radial nerve injuries?
Choose Ulnar and radial nerve injuries when the stem gives this contrasting pattern: Ulnar injury causes interossei weakness and medial hand sensory loss; radial injury causes wrist drop and dorsal hand sensory changes.
Quick answers
What is the fastest way to tell Median nerve injury from Ulnar and radial nerve injuries?
Median is thenar/lateral digits; ulnar is interossei/medial digits; radial is wrist extension/wrist drop.
What is the key clue for Median nerve injury?
Median nerve injury causes thenar weakness, carpal tunnel sensory symptoms in lateral 3.5 digits, and ape hand or hand of benediction depending lesion.
What is the key clue for Ulnar and radial nerve injuries?
Ulnar injury causes interossei weakness and medial hand sensory loss; radial injury causes wrist drop and dorsal hand sensory changes.