AANN Core Curriculum, 7th Edition, Ch. 23 Peripheral Nerve Injuries: Digital Version-Chapter 23

Chapter 23

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Peripheral nerve injuries may result from chronic compression or acute trauma and can cause pain, sensory loss, weakness, and lasting disability. Entrapment risk is increased by repetitive movements, pressure, anatomical abnormalities, systemic illness, and space-occupying lesions.<br /><br />Common entrapment syndromes include carpal tunnel syndrome (median nerve at the wrist), pronator teres syndrome (median nerve near the elbow), anterior interosseous nerve entrapment, ulnar neuropathy at the elbow or Guyon canal, radial nerve compression, posterior interosseous syndrome, neurogenic thoracic outlet syndrome, peroneal nerve entrapment, and meralgia paresthetica. Symptoms and examination findings help localize the lesion—for example, nocturnal hand tingling and thenar weakness in carpal tunnel syndrome, wrist drop with radial nerve injury, foot drop with peroneal nerve compression, and sensory symptoms over the lateral thigh in meralgia paresthetica. Some entrapments cause motor deficits without sensory loss.<br /><br />Assessment includes focused motor and sensory examinations and provocative maneuvers such as Tinel and Phalen tests. Electromyography and nerve conduction studies help locate injury, assess nerve function, and distinguish nerve from muscle disorders; ultrasound or MRI may identify compressive masses. Treatment generally begins with removing or reducing pressure, activity modification, splinting or bracing, medication, and physical or occupational therapy. Surgery is considered when conservative treatment fails, deficits progress, or a nerve is transected.<br /><br />Traumatic injuries may be open or closed. Neurapraxia is a temporary conduction disruption without axonal damage; axonotmesis disrupts axons but preserves their guiding structure; neurotmesis disrupts the nerve’s connective tissues and does not recover spontaneously. Axonal regeneration proceeds at roughly 1 mm per day. Examination, serial electrodiagnostic testing, and imaging guide diagnosis and treatment. Clean sharp transections generally require early repair; closed injuries are monitored, with exploration considered if recovery does not occur by about three months. Therapy, pain management, and timely referral are important.<br /><br />Neonatal brachial plexus palsy often improves with conservative care, though persistent weakness—especially severe injury with Horner syndrome—may warrant early surgical evaluation.

Keywords

peripheral nerve injury

entrapment neuropathy

carpal tunnel syndrome

ulnar neuropathy

radial nerve compression

peroneal nerve entrapment

meralgia paresthetica

electromyography

nerve conduction studies

brachial plexus palsy