Is sensation to the palm preserved in pronator teres syndrome?

Sensation to the Palm in Pronator Teres Syndrome

Yes, sensation to the palm is typically preserved in pronator teres syndrome because the compression of the median nerve occurs proximal to the palmar cutaneous branch.

Pathophysiology and Anatomical Considerations

Pronator teres syndrome (PTS) is a compression neuropathy affecting the median nerve as it passes through the proximal forearm. Understanding the anatomical basis helps explain the preservation of palm sensation:

• The median nerve passes between the two heads of the pronator teres muscle in the proximal forearm
• Compression typically occurs at the deep fascia of the superficial head of the pronator teres 1
• The palmar cutaneous branch of the median nerve branches off distal to the pronator teres, thus preserving palm sensation

Clinical Presentation and Sensory Distribution

The sensory symptoms in pronator teres syndrome differ from those in carpal tunnel syndrome in important ways:

• Patients typically experience paresthesia and sensory changes in the proximal forearm rather than the palm 2
• Symptoms include:
  • Tingling in the proximal third of the forearm 2
  • Weakness with certain movements
  • Numbness in the forearm rather than the palm
  • Pain in the forearm that may worsen with activity 3

Diagnostic Considerations

When evaluating a patient with suspected pronator teres syndrome, it's important to differentiate it from carpal tunnel syndrome:

• Preservation of palm sensation is a key distinguishing feature from carpal tunnel syndrome
• Ultrasound can demonstrate compression of the median nerve between the ulnar and humeral heads of the pronator teres muscle 2
• Electroneuromyography can confirm the diagnosis by localizing the site of nerve compression 2
• The flexor digitorum test can help identify if the compression is isolated to the pronator teres 1

Clinical Significance and Management

Understanding the preservation of palm sensation has important implications for diagnosis and treatment:

• Atypical carpal tunnel-like presentations with preserved palm sensation should prompt consideration of pronator teres syndrome 4
• Surgical decompression specifically targeting the deep fascia of the superficial head of the pronator teres is effective in 93% of cases 1
• Mini-invasive surgical approaches can be used to release the compressive structures while minimizing scarring 5
• Conservative management with physiotherapy may be beneficial in some cases, with improvement reported after 45 days of treatment 2

Potential Complications

In severe or prolonged cases, pronator teres syndrome can progress to include:

• Combined features of pronator teres syndrome and anterior interosseous nerve syndrome 4
• Motor deficits affecting hand dexterity
• Persistent pain and disability if not properly diagnosed and treated

Early recognition of the characteristic pattern of preserved palm sensation with forearm symptoms is crucial for timely diagnosis and appropriate management of this uncommon but important compression neuropathy.