What Is Radial Tunnel Syndrome?
Radial tunnel syndrome is a compressive neuropathy involving the posterior interosseous nerve (PIN) as it passes through the radial tunnel in the proximal forearm. It is characterized primarily by pain, rather than sensory loss or muscle weakness.
Diagnosis is clinical, and treatment typically begins with nonoperative measures. Surgical decompression is considered for persistent, refractory cases.
Symptoms
clinical descriptions consistently report:
- Deep, aching pain in the dorsoradial proximal forearm
- Pain that may extend from the lateral elbow toward the wrist
- Pain that increases with forearm rotation or lifting activities
- Localized tenderness, typically 3–5 cm distal to the lateral epicondyle
- Apparent weakness may be present, but this is attributed to pain inhibition, not true nerve denervation
Causes and Pathophysiology
Radial tunnel syndrome results from compression of the posterior interosseous nerve at one or more anatomic sites within the radial tunnel.
Documented compression sites include:
- Fibrous bands anterior to the radiocapitellar joint
- Radial recurrent vessels (the leash of Henry)
- The medial edge of the extensor carpi radialis brevis
- The proximal edge of the supinator muscle (arcade of Frohse), the most common entrapment site
Increased pressure within the radial tunnel has been demonstrated during provocative maneuvers that stretch the supinator muscle.
Risk Factors
High-quality evidence identifies repetitive, forceful forearm rotation (pronation–supination)—particularly with the elbow partially flexed—as a risk factor.
There is no high-quality evidence confirming that ergonomics, muscle imbalance, or generalized overuse alone independently cause the condition.
Radial Tunnel Syndrome vs. Similar Conditions
Lateral Epicondylitis (Tennis Elbow)
- Lateral epicondylitis presents with tenderness directly over the lateral epicondyle
- Radial tunnel syndrome presents with tenderness distal to the epicondyle
- The two conditions can coexist in a subset of patients
Posterior Interosseous Nerve Syndrome
- Posterior interosseous nerve syndrome is associated with true motor weakness
- Radial tunnel syndrome is defined by pain without objective motor deficit
Diagnosis
There is no single definitive diagnostic test for radial tunnel syndrome.
Diagnosis relies on:
- Careful medical history
- Physical examination, focusing on pain location and reproduction of symptoms
- Provocative maneuvers that increase pain at the radial tunnel
Diagnostic Studies
- Electrodiagnostic testing (EMG/NCV) is typically inconclusive, as pain fibers involved in radial tunnel syndrome are not well assessed by these studies
- MRI may be used selectively to evaluate muscle changes or exclude other structural causes but is often normal
Treatment Options
Conservative Treatment
Evidence supports initial nonoperative management, including:
- Activity modification
- Temporary splinting
- Nonsteroidal anti-inflammatory drugs (NSAIDs)
Corticosteroid injections into the radial tunnel have demonstrated:
- Short-term improvement in pain
- Sustained pain relief in a subset of patients at long-term follow-up
Surgery
Surgical radial tunnel release is reserved for patients who do not improve after extensive nonoperative treatment.
Reported outcomes indicate:
- Variable success rates
- Recovery may take 9–18 months
- Less favorable outcomes in patients with coexisting conditions or workers’ compensation claims
Recovery and Prognosis
- Improvement with nonoperative care has been documented, particularly following targeted injections
- Surgical outcomes are variable, and full recovery may be prolonged
- There is no high-quality evidence supporting a uniform recovery timeline applicable to all patients
When to See a Doctor
Based on verified evidence, medical evaluation is appropriate when:
- Forearm pain is persistent and localized distal to the lateral epicondyle
- Pain is reproducible with forearm rotation or lifting
- Symptoms do not improve with initial conservative measures
There is no high-quality evidence defining exact timelines for when evaluation must occur.
Frequently Asked Questions
What causes radial tunnel syndrome?
Radial tunnel syndrome is caused by compression of the posterior interosseous nerve within the radial tunnel at specific anatomic sites.
What are the main symptoms?
The primary symptom is deep, aching forearm pain, often worsened by forearm rotation or lifting, without true numbness or muscle weakness.
How is radial tunnel syndrome diagnosed?
Diagnosis is clinical, based on history, physical examination, and symptom reproduction with specific maneuvers. Imaging and nerve studies are supportive but not definitive.
How is radial tunnel syndrome treated?
Treatment begins with conservative measures, including activity modification, splinting, and NSAIDs. Surgery is considered only for persistent, refractory cases.
How long does radial tunnel syndrome last?
There is no high-quality evidence supporting a specific duration for radial tunnel syndrome.
Can exercises cure radial tunnel syndrome?
There is no high-quality evidence supporting exercises alone as a definitive cure.
Is radial tunnel syndrome the same as tennis elbow?
No. While symptoms may overlap, the conditions differ in anatomic cause and tenderness location, and they may coexist.
APA References List
Cleveland Clinic. (2021, November 23). Nerve compression syndromes: Causes, treatment & prevention. https://my.clevelandclinic.org/health/diseases/22137-nerve-compression-syndrome
Cleveland Clinic. (2025, January 6). Radial tunnel syndrome: Symptoms, causes & treatment. https://my.clevelandclinic.org/health/diseases/15658-radial-tunnel-syndrome
Merck & Co., Inc. (2025). Radial tunnel syndrome. MSD Manual Professional Edition. https://www.msdmanuals.com/professional/musculoskeletal-and-connective-tissue-disorders/hand-disorders/radial-tunnel-syndrome
Moradi, A., Ebrahimzadeh, M. H., & Jupiter, J. B. (2015). Radial tunnel syndrome, diagnostic and treatment dilemma. Archives of Bone and Joint Surgery, 3(3), 156–162. https://pmc.ncbi.nlm.nih.gov/articles/PMC4507067/
Shamrock, A. G., & Das, J. M. (2023, August 14). Radial tunnel syndrome. In StatPearls [Internet]. StatPearls Publishing. https://www.ncbi.nlm.nih.gov/books/NBK555937/
Wheeler, R., & DeCastro, A. (2023, May 1). Posterior interosseous nerve syndrome. In StatPearls [Internet]. StatPearls Publishing. https://www.ncbi.nlm.nih.gov/books/NBK541046/
Woon, C. (2025, May 29). Radial tunnel syndrome. Orthobullets. https://www.orthobullets.com/hand/6024/radial-tunnel-syndrome