From the Guidelines
The physical examination for carpal tunnel syndrome should include a combination of inspection, Tinel's test, Phalen's test, carpal compression test, two-point discrimination testing, and measurement of grip and pinch strength to evaluate median nerve compression at the wrist. When evaluating a patient for carpal tunnel syndrome, it is essential to begin with a thorough inspection for thenar muscle atrophy, which indicates advanced disease 1. The following tests can be performed:
- Tinel's test: tapping over the median nerve at the wrist to check for tingling or electric sensations radiating into the thumb, index, middle, and radial half of the ring finger
- Phalen's test: having the patient flex both wrists maximally for 60 seconds to reproduce symptoms
- Carpal compression test: applying direct pressure over the carpal tunnel for 30 seconds to check for symptom reproduction
- Two-point discrimination testing: assessing sensory function, with values greater than 6mm suggesting nerve compression
- Measurement of grip and pinch strength: evaluating motor function These tests are valuable because they directly stress the median nerve where it passes through the carpal tunnel, helping to distinguish carpal tunnel syndrome from other conditions that may cause similar symptoms, such as cervical radiculopathy or peripheral neuropathy 1. It is crucial to note that while these tests can be useful in diagnosing carpal tunnel syndrome, the effectiveness of different treatments, including surgical and non-surgical options, should be considered in the context of the patient's overall condition and medical history 1.
From the Research
Physical Exam for Carpal Tunnel Syndrome
The physical exam for carpal tunnel syndrome (CTS) involves various maneuvers to diagnose the condition. The following are some of the key findings:
- Hypalgesia in the median nerve territory has a likelihood ratio (LR) of 3.1 for diagnosing CTS 2
- Classic or probable Katz hand diagram results have an LR of 2.4 for diagnosing CTS 2
- Weak thumb abduction strength has an LR of 1.8 for diagnosing CTS 2
- Unlikely Katz hand diagram results have an LR of 0.2 against diagnosing CTS 2
- Normal thumb abduction strength has an LR of 0.5 against diagnosing CTS 2
Traditional Findings with Little Diagnostic Value
Some traditional findings have little or no diagnostic value for CTS, including:
- Nocturnal paresthesias 2
- Phalen and Tinel signs, although Phalen's test has been found to be useful in some studies 2, 3
- Thenar atrophy 2
- 2-point, vibratory, and monofilament sensory testing 2
Other Diagnostic Maneuvers
Other less commonly used maneuvers, such as the square wrist sign, flick sign, and closed fist sign, require validation by other studies before they can be recommended 2
- The hand elevation test may be used in isolation and is superior to questionnaires and other physical signs in the clinical diagnosis of CTS 4
- The tourniquet, carpal compression, and Phalen's tests are a good combination for diagnosing CTS 4
Prognosis and Quality of Life
The Phalen test and Tinel sign can be useful in the prognosis and impact on quality of life of patients with CTS undergoing surgical treatment 5
- The remission of the Phalen test and Tinel sign can be prognostic factors favorable to the clinical course, with improved quality of life 5