Peripheral Nerve Entrapment Syndromes

A concise guide to localizing common compressive neuropathies, key exam findings, and practical management.

Topic: Neuromuscular Level: Intro / Intermediate Tags: entrapment, carpal-tunnel, cubital-tunnel, peroneal, meralgia, tarsal-tunnel

Overview

Peripheral nerve entrapment occurs when a nerve is compressed within a fixed space or under repetitive mechanical stress. Typical symptoms include numbness, tingling, burning pain, and focal weakness in a nerve distribution. Chronic entrapment risks denervation and atrophy—early localization matters. Risk factors include repetitive use, trauma, pregnancy, obesity, diabetes, and hypothyroidism.

Clinician tip: Differentiate entrapment from radiculopathy by mapping sensory loss and testing a single nerve’s key muscles and reflexes.

Common entrapment syndromes

Median nerve — Carpal tunnel

Deficits: thumb–middle finger numbness, hand clumsiness; APB weakness. Site: anterior wrist. Tx: night splint, ergonomics, steroid injection, surgical release if persistent.

Ulnar nerve — Cubital tunnel

Deficits: ring/little finger numbness; weak interossei, grip. Site: ulnar groove at elbow. Tx: avoid prolonged flexion, padding/splint; decompression if refractory.

Radial nerve — Spiral groove

Deficits: dorsum hand numbness; wrist drop. Site: posterior humerus (compression/fracture). Tx: relieve pressure, evaluate fracture; wrist splint.

Lateral femoral cutaneous — Meralgia paresthetica

Deficits: burning/numb lateral thigh (sensory only). Site: under inguinal ligament. Tx: weight loss, loose clothing, pregnancy resolution; NSAIDs ± local block.

Common peroneal — Fibular head

Deficits: foot drop (weak dorsiflexion), lateral shin/dorsal foot numbness. Site: compression at fibular neck (leg crossing/trauma). Tx: avoid compression, PT, AFO; treat trauma.

Tibial nerve — Tarsal tunnel

Deficits: plantar pain/numbness; intrinsic foot weakness. Site: medial ankle tunnel. Tx: footwear, orthotics, PT; surgical release for severe cases.

Key differences at a glance

Nerve	Deficits (sensory/motor)	Typical entrapment site
Median	Thumb–middle finger numbness; APB weakness	Carpal tunnel (anterior wrist)
Ulnar	Ring + little finger numbness; weak interossei	Cubital tunnel (ulnar groove at elbow)
Radial	Dorsal hand numbness; wrist drop	Spiral groove of humerus
Lateral femoral cutaneous	Lateral thigh paresthesia (sensory only)	Under inguinal ligament
Common peroneal	Foot drop; lateral shin/dorsal foot numbness	Fibular head/neck
Tibial	Plantar pain/numbness; intrinsic weakness	Tarsal tunnel (medial ankle)

Work-up snapshot

Detailed sensory map and manual muscle testing for a single nerve’s key muscles.
Tinel/Phalen (carpal tunnel), elbow flexion test (ulnar), percussion at fibular head (peroneal).
NCS/EMG for diagnostic uncertainty, severity grading, or pre-op planning.
Imaging (US/MRI) when mass lesion or anatomic variant is suspected.

Red flag: Progressive weakness with marked atrophy or acute foot drop warrants expedited electrodiagnostics and specialty referral.

Treatment snapshot

Ergonomics, activity modification, splinting/orthoses; neuropathic pain measures as needed.
Local steroid injection for carpal tunnel or tarsal tunnel in select cases.
Early therapy for gait-safety risks (AFO for peroneal palsy).
Surgical decompression for persistent deficits or denervation on EMG despite conservative care.

Pearl: Document provocative positions (e.g., elbow flexion, leg crossing) and sleep posture—small habit changes often resolve symptoms.

References

Practical reviews on compressive neuropathies; electrodiagnostic guidance for entrapment neuropathies.

Educational discussion. Not a substitute for clinical judgment. Consider local protocols and individual factors.