🔑 Key Learning

  • Carpal tunnel syndrome = compression of the median nerve at the wrist → paraesthesia in lateral 3.5 fingers.
  • Cubital tunnel syndrome = compression of the ulnar nerve at the elbow → medial hand paraesthesia, claw hand.
  • Radial tunnel syndrome = compression of the posterior interosseous nerve → dorsal forearm pain, worse with resisted extension.

✋ Carpal Tunnel Syndrome

🧬 Pathophysiology

  • Compression of the median nerve within the carpal tunnel at the wrist.
  • The carpal tunnel contains:
    • 9 flexor tendons
    • Median nerve
  • RFs: Repetitive activities (e.g. typing, painting, gardening), pregnancy, diabetes, RA, hypothyroidism, obesity
Figure 229: The Carpal Tunnel. OpenStax College, CC BY 3.0.

👀 Clinical Features

  • Sensory:
    • Paraesthesia/pain in the lateral 3.5 fingers and lateral palm (excluding the thenar eminence due to palmar cutaneous branch)
    • Worse at night, often wakes patients from sleep
    • Patients may shake hands for relief
  • Motor:
    • Weak grip
    • Difficulty with fine motor tasks
    • Thenar wasting in advanced disease

🧪 Examination

  • Phalen’s test: wrist flexion for 60 seconds reproduces symptoms
  • Tinel’s test: tapping over the median nerve reproduces tingling
  • Thenar wasting, reduced sensation, weak thumb abduction
Figure 230: Thenar wasting in a patient with untreated carpal tunnel syndrome.

🔍 Investigations

  • Clinical diagnosis
  • Nerve conduction studies: used to confirm and assess severity

💊 Management

  • Mild-moderate:
    • Nocturnal wrist splinting
    • Corticosteroid injection
  • Severe/persistent:
    • Nerve conduction studies
    • Surgical decompression (carpal tunnel release)

🦵 Cubital Tunnel Syndrome

🧬 Pathophysiology

  • Compression of the ulnar nerve in the cubital tunnel (between the medial epicondyle and olecranon)
Figure 231: The ulnar tunnel - a site of entrapment ulnar neuropathy. InjuryMap, CC BY-SA 4.0.

👀 Clinical Features

  • Sensory:
    • Paraesthesia in medial 1.5 fingers and hypothenar eminence
  • Motor:
    • Weak grip
    • Clawing of 4th/5th digits
    • Wasting of interosseous muscles

🧪 Examination

  • Tinel’s at the elbow
  • Elbow flexion test: symptoms reproduced with prolonged flexion
  • Froment’s sign (paper grip test): tests adductor pollicis weakness

💊 Management

  • Avoid prolonged elbow flexion
  • Elbow pad/night splint
  • Nerve conduction studies if persistent
  • Surgical decompression if progressive symptoms

💥 Radial Tunnel Syndrome

🧬 Pathophysiology

  • Compression of the posterior interosseous nerve (a branch of the radial nerve) in the radial tunnel (just distal to lateral epicondyle)

👀 Clinical Features

  • Vague dull ache or burning pain over dorsolateral forearm
  • Pain worse with resisted supination/pronation
  • No sensory changes (PIN is motor only)
  • Worse at night, may mimic lateral epicondylitis

🧪 Examination

  • Pain with resisted middle finger extension or thumb extension
  • Tenderness 3–5 cm distal to lateral epicondyle
  • Rule out tennis elbow (more focal, tender directly over epicondyle)

💊 Management

  • Activity modification, NSAIDs
  • Splinting
  • Physiotherapy
  • Surgical decompression if refractory

📝 Exam Clues & Clinchers

  • Median nerve = carpal tunnel, nocturnal symptoms, thenar wasting
  • Ulnar nerve = medial 1.5 fingers, claw hand, Froment’s sign
  • Posterior interosseous nerve = dorsal forearm pain, no sensory deficit