Carpal Tunnel Syndrome: Median Nerve Compression at the Wrist

Carpal tunnel syndrome (CTS) is the clinical syndrome resulting from compression of the median nerve within the carpal tunnel at the wrist. It is the most common entrapment neuropathy.

Anatomy

The carpal tunnel is a narrow osteofibrous canal formed by the carpal bones (floor/walls) and the transverse carpal ligament (roof). It contains the median nerve and nine flexor tendons.

Pathophysiology

Increased pressure within the tunnel (from tendon sheath thickening, synovitis, edema, mass lesions, or anatomic variants) compresses the median nerve, causing ischemia and demyelination.

Clinical Presentation

• Sensory: Numbness, tingling, burning in median nerve distribution (thumb, index, middle, radial half of ring finger; spares thenar eminence — palmar cutaneous branch branches proximal).
• Nocturnal symptoms: Wakes patient; shaking hand relieves.
• Motor (late): Thenar wasting, weakness of opposition, abduction, "ape hand" deformity.
• Provocative tests: Tinel's sign at wrist, Phalen's maneuver (wrist flexion 60 sec), Durkan's compression test.

Diagnosis

• Clinical history and exam (high specificity/sensitivity combined).
• Nerve conduction studies (NCS) / electromyography (EMG): confirm, grade severity, rule out other neuropathies (cervical radiculopathy, pronator teres syndrome).
• Ultrasound: cross-sectional area of median nerve at tunnel inlet > 10–12 mm² supportive.

Management

Conservative

• Wrist splint in neutral (night ± day)
• Activity modification, ergonomic optimization
• NSAIDs (limited evidence)
• Corticosteroid injection (diagnostic + therapeutic; temporary relief)

Surgical

• Carpal tunnel release (open or endoscopic): division of transverse carpal ligament.
• Indicated for persistent/severe symptoms, thenar wasting, NCS-confirmed severe compression, failed conservative trial.
• High success rate (>90% symptom relief); low complication rate.

Early diagnosis and treatment prevent irreversible nerve damage. Bilateral symptoms are common; systemic causes (diabetes, hypothyroidism, pregnancy, amyloidosis) should be screened.