What are the signs of carpal tunnel syndrome?

Signs of Carpal Tunnel Syndrome

The diagnosis of carpal tunnel syndrome (CTS) can be made through clinical assessment, with key signs including enlargement and flattening of the median nerve, bowing of the flexor retinaculum, and characteristic sensory and motor symptoms in the median nerve distribution. 1

Clinical Signs

• Pain, numbness, and tingling in the distribution of the median nerve (thumb, index finger, middle finger, and radial half of the ring finger) are classic symptoms that should prompt consideration of CTS 2, 3
• Nocturnal pain associated with tingling and numbness is particularly characteristic of CTS 4
• Burning dysesthetic wrist pain, loss of grip strength, and decreased dexterity are common manifestations 5
• Proximal radiation of symptoms along the volar forearm, medial arm, and shoulder may occur in some cases 5
• Symptoms often worsen at night and can be exacerbated by forceful activity and extreme wrist positions 5
• Bilateral CTS may be an early sign of certain systemic conditions or amyloidosis 6

Physical Examination Findings

• Hypalgesia (decreased pain sensation) in the median nerve distribution is a useful diagnostic finding 3
• Square wrist sign (ratio of wrist width to thickness) can help identify patients at risk 3
• Hand symptom diagram showing classic or probable pattern of symptoms supports the diagnosis 3
• Decreased grip strength and hand weakness may be present in more advanced cases 7
• Restricted hand movement can occur as the condition progresses 7

Diagnostic Imaging Findings

• Ultrasound can demonstrate:

  • Enlargement of the median nerve cross-sectional area at various locations in the wrist 1
  • Space-occupying lesions within the carpal tunnel 1
  • Anatomic variants including bifid median nerve and persistent median artery 1
  • Tendon pathology in the carpal tunnel 1

• MRI, while not routinely indicated, can show:

  • Enlargement and flattening of the median nerve 1
  • Bowing of the flexor retinaculum 1
  • Space-occupying lesions and anatomic variants 1

Clinical Pearls and Pitfalls

• Nerve conduction studies remain the gold standard test for confirming CTS diagnosis, though they can have false positive and false negative results 4
• The diagnosis should be based on a combination of history, physical examination, and electrophysiological studies rather than any single test 4
• Several conditions can present with similar symptoms to CTS, requiring thorough evaluation to establish the correct diagnosis 2
• CTS is particularly common during pregnancy, with prevalence reported as high as 62%, and median nerve function is impaired in virtually all pregnant women during the third trimester, even without symptoms 5
• While the American Academy of Orthopedic Surgeons guidelines note limited evidence supporting routine ultrasound for CTS diagnosis, multiple systematic reviews demonstrate it to be highly sensitive and specific when compared with clinical assessment and electrophysiologic studies 1