Do patients with carpal tunnel syndrome (CTS) typically experience a lack of sensation on the palm?

Sensory Distribution in Carpal Tunnel Syndrome

Patients with carpal tunnel syndrome (CTS) typically experience sensory disturbances in the median nerve distribution of the palm, but sensory symptoms frequently extend beyond the classic median nerve territory. 1, 2

Typical Sensory Patterns in CTS

• CTS presents with sensory disturbances primarily affecting the median nerve distribution in the hand, which includes:

  • Thumb
  • Index finger
  • Middle finger
  • Radial half of the ring finger
  • Palmar surface of these digits 1, 3

• The American College of Radiology notes that CTS typically presents with:

  • Nocturnal paresthesias
  • Prominent palmar sensory loss in median nerve distribution
  • Positive Tinel's and Phalen's signs at the wrist
  • Symptoms exacerbated by wrist flexion or extension 1

Important Clinical Considerations

• Research shows sensory disturbances occur most frequently in areas innervated by the median nerve (index finger, 94%), but also with surprising frequency in non-median nerve areas (little finger, 39%) 2

• The palmar cutaneous branch of the median nerve, which supplies sensation to part of the palm, branches proximal to the carpal tunnel and is therefore typically spared in isolated CTS 1

• This preservation of palmar cutaneous nerve function can help differentiate CTS from more proximal median nerve compressions like Pronator Teres Syndrome 1

• Objective sensory testing shows poor correlation with electrophysiological findings, suggesting that patient-reported symptoms remain the most important diagnostic tool 2

Diagnostic Implications

• An "atypical" distribution of symptoms is actually quite common in CTS and should not discourage diagnosis 2

• When evaluating patients with suspected CTS, clinicians should:

  • Consider that sensory symptoms may extend beyond the classic median nerve distribution
  • Not rule out CTS based solely on symptoms affecting the little finger or other "non-median" areas
  • Use electrodiagnostic studies to confirm diagnosis in atypical presentations 3, 2

• The presence of thenar atrophy is a late finding and highly specific for CTS 3

Clinical Pitfalls to Avoid

• Assuming that sensory symptoms must strictly follow textbook median nerve distribution
• Dismissing CTS diagnosis when symptoms affect areas outside median nerve territory
• Relying solely on objective sensory testing, which correlates poorly with electrophysiological findings 2
• Failing to consider concurrent compression syndromes (approximately 6% of CTS cases may have concurrent pronator syndrome) 1

By understanding the variable sensory patterns in CTS, clinicians can avoid misdiagnosis and ensure appropriate treatment for patients with this common nerve compression syndrome.