Focused examination of the median, ulnar, and radial nerves in the hand including motor testing, sensory assessment, and provocative tests for carpal tunnel and cubital tunnel syndromes.
Hand nerve examination requires systematic assessment of the three main nerves: median, ulnar, and radial. Examiners expect you to know the motor and sensory distributions of each nerve, perform provocative tests correctly, and differentiate between high and low nerve lesions.
High-Yield Exam Summary
Median Nerve (C6-T1):
Ulnar Nerve (C8-T1):
Radial Nerve (C5-T1):
Memory Aid - "LOAF" Muscles (Median Nerve):
Everything else in the hand is ULNAR!
Abductor Pollicis Brevis (APB):
Opposition:
Anterior Interosseous Nerve (AIN):
Distribution:
Best Test Area:
Note: Palm is spared in carpal tunnel syndrome (palmar cutaneous branch exits proximal to tunnel)
Carpal tunnel syndrome
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Tingling or numbness in median nerve distribution within 60 seconds
Carpal tunnel syndrome - wrist flexion increases pressure in carpal tunnel
Ability to detect true positives
Ability to exclude false positives
Carpal tunnel syndrome
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Paresthesias radiating into median nerve territory (thumb, index, middle finger)
Carpal tunnel syndrome - demyelination/regeneration at compression site
Ability to detect true positives
Ability to exclude false positives
Carpal tunnel syndrome
Reproduction of median nerve paresthesias within 30 seconds
Carpal tunnel syndrome - most sensitive provocation test
Ability to detect true positives
Ability to exclude false positives
Carpal tunnel syndrome
Paresthesias in median nerve distribution
Carpal tunnel syndrome (alternative to Phalen's)
Ability to detect true positives
Ability to exclude false positives
First Dorsal Interosseous (FDI):
Finger Abduction/Adduction:
Adductor Pollicis:
Hypothenar Muscles:
Distribution:
Best Test Area:
Key Point:
Ulnar nerve palsy
Flexion of thumb IP joint (uses FPL instead of weak adductor pollicis)
Ulnar nerve palsy with adductor pollicis weakness - compensatory FPL activation
Ability to detect true positives
Ability to exclude false positives
Froment's Sign Explained:
Ulnar nerve palsy
Little finger remains abducted (cannot adduct with other fingers)
Ulnar nerve palsy - weak third palmar interosseous, unopposed EDM
Ability to detect true positives
Ability to exclude false positives
Cubital tunnel syndrome
Paresthesias in ulnar nerve distribution (ring and little finger)
Cubital tunnel syndrome - elbow flexion increases pressure in cubital tunnel
Ability to detect true positives
Ability to exclude false positives
Cubital tunnel syndrome
Paresthesias radiating into ulnar nerve territory (ring and little finger)
Cubital tunnel syndrome - ulnar nerve irritability
Ability to detect true positives
Ability to exclude false positives
Wrist Extension (ECRL, ECRB, ECU):
Finger Extension (EDC):
Thumb Extension (EPL):
Posterior Interosseous Nerve (PIN):
Superficial Radial Nerve (SRN):
Note:
De Quervain's (affects SRN region)
Pain over radial styloid (first dorsal compartment)
De Quervain's tenosynovitis (note: SRN may be tender in Wartenberg syndrome)
Ability to detect true positives
Ability to exclude false positives
Classic Ulnar Claw:
Ulnar Paradox:
Bouvier's Test:
| nerve | motor | sensory | clinicalSign |
|---|---|---|---|
| High Median | FPL, FDP 1-2, pronators, FCR, all LOAF | Full median territory | Can't make OK sign, weak pinch |
| Low Median (CTS) | APB, opponens, FPB, lumbricals 1-2 | Spares palm (cutaneous branch) | Thenar wasting, weak opposition |
| AIN (Median) | FPL, FDP 1-2, pronator quadratus | None (pure motor) | Flat OK sign, no sensory loss |
| High Ulnar | FDP 3-4 + all hand intrinsics | Full ulnar territory | Less obvious claw (ulnar paradox) |
| Low Ulnar (Guyon's) | Hand intrinsics only | May spare dorsum (DCB) | More obvious claw, Froment's |
| High Radial | Wrist + finger + thumb extensors | Full radial territory | Wrist drop |
| PIN (Radial) | Finger + thumb extensors only | None (pure motor) | Finger drop, wrist extension OK |
"54-year-old woman with numbness and tingling in her right hand, waking her at night."
High-Yield Exam Summary