Cervical Radiculopathy vs Thoracic Outlet Syndrome vs Carpal Tunnel
Referred Pain Patterns · 8 min read · 2026-02-07
Introduction
A patient presents with arm pain, numbness, and tingling. Three conditions must be considered: cervical radiculopathy (nerve root compression in the neck), thoracic outlet syndrome (TOS — compression in the costoclavicular space), and carpal tunnel syndrome (median nerve compression at the wrist). Each produces upper limb symptoms, but the patterns are distinct.
Cervical Radiculopathy
Cause: Disc herniation or foraminal stenosis compressing a cervical nerve root.
Pattern: Symptoms follow a dermatomal distribution. C6 radiculopathy affects the thumb and index finger. C7 affects the middle finger. C8 affects the ring and little finger. Pain radiates from the neck down the arm in a predictable path.
Key findings:
- Neck pain with radicular radiation
- Dermatomal sensory loss
- Myotomal weakness (C5 — deltoid, C6 — biceps/wrist extensors, C7 — triceps/wrist flexors, C8 — finger flexors/intrinsics)
- Reflex changes (C5–6 biceps, C7 triceps)
- Spurling's test positive (axial compression with extension and rotation reproduces radicular symptoms)
Thoracic Outlet Syndrome
Cause: Compression of the brachial plexus and/or subclavian vessels between the scalene muscles, first rib, and clavicle.
Pattern: Symptoms are often vague and do not follow a single nerve or dermatome. Patients describe diffuse arm heaviness, numbness in the medial forearm and hand (lower trunk/C8–T1 territory), and symptoms provoked by overhead positions.
Key findings:
- Symptoms with arms overhead (hanging washing, sleeping with arms up)
- Medial forearm and hand numbness (ulnar distribution)
- Possible vascular symptoms: pallor, coolness, Raynaud's-like color changes
- Roos test (elevated arm stress test — 3 minutes of opening/closing fists with arms at 90° abduction)
- Adson's test, Wright's test (though specificity is debated)
- No dermatomal pattern, no reflex changes
Carpal Tunnel Syndrome
Cause: Median nerve compression beneath the flexor retinaculum.
Pattern: Numbness in the median nerve territory — thumb, index, middle, radial half of ring finger. Nocturnal symptoms are characteristic.
Key findings:
- Night symptoms, shaking hands for relief
- Phalen's and Tinel's positive at the wrist
- Thenar weakness/wasting in advanced cases
- Symptoms are distal only — no neck or proximal arm pain
- No reflex changes
The Differentiation Framework
Clinical Pearl
Double crush syndrome: compression at one site (e.g., cervical spine) can make a nerve more susceptible to compression at a second site (e.g., carpal tunnel). Up to 30% of carpal tunnel patients may have concurrent cervical pathology. Always examine the neck in patients with carpal tunnel symptoms.
Summary
Dermatomal pattern + neck pain + Spurling's = cervical radiculopathy. Diffuse medial arm symptoms + overhead provocation = TOS. Nocturnal median territory numbness + Phalen's = carpal tunnel. The three conditions can coexist, so always think systematically.