What physical assessment tests are used to diagnose carpal tunnel syndrome?

Physical Assessment Tests for Carpal Tunnel Syndrome

The most accurate physical examination tests for diagnosing carpal tunnel syndrome are the carpal compression test and Phalen's wrist flexion test, while hypalgesia in the median nerve distribution and weak thumb abduction strength are the most useful clinical findings to confirm the diagnosis. 1, 2

Primary Diagnostic Maneuvers

Most Accurate Tests

• Carpal Compression Test: Apply direct pressure over the median nerve at the wrist to reproduce symptoms. This test, along with Phalen's test, demonstrates the highest overall accuracy for CTS diagnosis. 1

• Phalen's Wrist Flexion Test: Have the patient maintain maximum wrist flexion for 60 seconds. Reproduction of paresthesias or pain indicates a positive test. This maneuver has the highest overall accuracy among provocative tests. 1, 3

Moderately Useful Clinical Findings

• Hypalgesia Testing: Assess for decreased pain sensation in the median nerve territory (palmar aspect of thumb, index, middle fingers, and radial half of ring finger). This finding has a likelihood ratio of 3.1, making it the single most useful physical finding. 2

• Thumb Abduction Strength: Test strength of thumb abduction against resistance. Weak thumb abduction has a likelihood ratio of 1.8 for CTS, while normal strength argues against the diagnosis (LR 0.5). 2

• Flick Sign: Ask patients to demonstrate how they relieve their symptoms. Patients with CTS characteristically shake or flick their hands, similar to shaking down a thermometer. 4

Less Reliable Tests

Tinel's Sign

• Tap over the median nerve at the wrist to elicit paresthesias in the median nerve distribution. 3
• Important caveat: While widely used, Tinel's sign has little diagnostic value for confirming CTS but is more specific for detecting axonal damage in moderate to severe cases. 1, 2

Hand Symptom Diagrams (Katz Hand Diagram)

• Classic or probable patterns on standardized hand diagrams have a likelihood ratio of 2.4, while unlikely patterns argue strongly against CTS (LR 0.2). 2

Tests With No Diagnostic Value

The following commonly performed tests have little or no diagnostic value and should not be relied upon: 2

• Nocturnal paresthesias (as a standalone finding)
• Two-point discrimination testing
• Vibratory sensation testing
• Monofilament sensory testing
• Thenar atrophy (indicates severe, late-stage disease only)

Clinical Examination Approach

Begin by assessing for the characteristic symptom pattern: pain and paresthesias in the median nerve distribution (thumb, index, middle fingers, and radial half of ring finger). 4, 5

Perform the high-yield examination sequence: 1, 2

1. Carpal compression test (direct pressure over median nerve)
2. Phalen's wrist flexion test (60 seconds of maximum flexion)
3. Hypalgesia testing in median nerve territory
4. Thumb abduction strength testing
5. Observe for the flick sign

Confirmation and Severity Assessment

• Patients with typical symptoms and positive physical examination findings do not require additional testing for diagnosis. 4

• Electrodiagnostic studies should be obtained when: 6, 4

  • Presentation is atypical
  • Surgical decompression is planned (to determine severity and prognosis)
  • Diagnosis remains uncertain after clinical evaluation

• Ultrasound measurement of median nerve size is highly sensitive and specific compared to clinical assessment and can be used in selected circumstances. 6, 7

Common Pitfalls to Avoid

• Do not rely solely on Tinel's sign or Phalen's test in isolation—these have limited diagnostic value when used alone. 2

• Do not perform extensive sensory testing with two-point discrimination, vibration, or monofilament testing, as these provide no diagnostic value for CTS. 2

• Do not mistake normal nocturnal paresthesias for a diagnostic finding—this symptom alone has no discriminatory value. 2