Is sensation intact on the palm in patients with carpal tunnel syndrome?

Sensation in Carpal Tunnel Syndrome

In carpal tunnel syndrome (CTS), sensation in the palm is typically preserved because the palmar cutaneous branch of the median nerve, which supplies sensation to the palm, branches off proximal to the carpal tunnel and is not affected by compression within the tunnel. 1

Anatomical Basis for Preserved Palmar Sensation

• The median nerve divides into several branches:

  • The palmar cutaneous branch separates from the median nerve approximately 5 cm proximal to the wrist crease, traveling superficially and not passing through the carpal tunnel
  • The main median nerve trunk continues through the carpal tunnel, supplying sensation to the thumb, index, middle, and radial half of the ring finger

• This anatomical arrangement explains why:

  • Palm sensation remains intact in typical CTS cases
  • Sensory symptoms predominantly affect the fingers in the median nerve distribution (thumb, index, middle fingers, and radial half of ring finger)

Clinical Presentation and Diagnostic Significance

• According to the American College of Radiology, CTS typically presents with 1:

  • Nocturnal paresthesias
  • Sensory loss in median nerve distribution of the fingers
  • Positive Tinel's and Phalen's signs at the wrist
  • Symptoms exacerbated by wrist flexion or extension
  • Preserved palmar sensation (important diagnostic feature)

• The preservation of palm sensation helps distinguish CTS from more proximal median nerve compression syndromes 1:

  • In Pronator Teres Syndrome (compression at the elbow), palm sensation may be affected
  • This distinction is clinically important for proper diagnosis and treatment planning

Diagnostic Implications

• When evaluating suspected CTS, clinicians should specifically test sensation in both the palm and fingers 2:

  • Finding intact palm sensation with impaired finger sensation supports a CTS diagnosis
  • Finding impaired sensation in both palm and fingers suggests a more proximal compression

• The American College of Radiology notes that electrodiagnostic studies can confirm CTS diagnosis in atypical presentations, but may miss this important clinical distinction 1

Clinical Relevance

• Understanding this pattern of sensory preservation is crucial for:
  • Accurate diagnosis of CTS
  • Distinguishing CTS from other median nerve compression syndromes
  • Avoiding misdiagnosis that could lead to inappropriate treatment
  • Proper patient education about expected symptoms

This pattern of preserved palm sensation with affected finger sensation is a key clinical feature that helps clinicians correctly identify carpal tunnel syndrome and distinguish it from other conditions affecting the median nerve.