Extensor Pollicis Longus and Brevis Trigger Points

Introduction

The extensor pollicis longus (EPL) and extensor pollicis brevis (EPB) are key forearm muscles responsible for thumb extension and wrist stabilization. When trigger points develop in these muscles, they can cause pain in the thumb, wrist, and forearm, often mimicking De Quervain’s tenosynovitis, carpal tunnel syndrome, or arthritis.

Name and Area

  • Name: Extensor Pollicis Longus (EPL) and Extensor Pollicis Brevis (EPB)

  • Area:

    • EPL: Runs from the posterior ulna to the distal phalanx of the thumb.

    • EPB: Runs from the posterior radius to the base of the proximal phalanx of the thumb.

Indications

Extensor pollicis longus and brevis trigger points may contribute to:

  • Pain in the Thumb and Wrist (Mistaken for De Quervain’s Tenosynovitis or Carpal Tunnel Syndrome)

  • Pain That Radiates to the Forearm (Can Mimic Radial Nerve Compression or Arthritis)

  • Weakness in Thumb Extension (Difficulty Opening Jars, Holding a Pen, or Using a Smartphone)

  • Pain When Gripping, Pinching, or Extending the Thumb (Common in Gamers, Texters, and Writers)

  • Forearm Fatigue With Repetitive Use (E.g., Typing, Playing an Instrument, Knitting, or Woodworking)

  • Pain That Worsens With Repetitive Wrist and Thumb Movements (E.g., Scrolling, Lifting, or Texting)

Pain from these muscles is often mistaken for De Quervain’s tenosynovitis, arthritis, or radial nerve compression.

Muscle Action

  • Extensor Pollicis Longus (EPL):

    • Extends the Thumb (Distal Joint) and Retracts It From the Palm

    • Assists in Wrist Extension and Radial Deviation

  • Extensor Pollicis Brevis (EPB):

    • Extends the Thumb at the Proximal Joint

    • Assists in Abduction and Stabilization of the Thumb

The EPL and EPB are essential for gripping, fine motor tasks, and wrist stabilization.

Signs and Symptoms

Individuals with extensor pollicis longus and brevis trigger points often report:

  • Pain in the Thumb and Wrist, Particularly Along the Thumb Side of the Forearm

  • Difficulty Extending the Thumb or Moving It Away From the Palm

  • Weakness When Pinching or Gripping (E.g., Holding a Key, Writing, or Using a Phone)

  • Pain That Worsens With Repetitive Thumb Movements (E.g., Scrolling on a Phone, Playing an Instrument, Sewing, or Knitting)

  • Burning or Aching Sensation in the Forearm (Can Be Mistaken for Radial Nerve Compression)

  • Stiffness or Clicking in the Thumb Joint (Mistaken for Arthritis or Tendinitis)

Pain worsens with repetitive thumb extension, gripping, or forearm movements.

Perpetuating Factors

Common causes of extensor pollicis longus and brevis trigger points include:

  • Repetitive Thumb Movements (Texting, Scrolling, Playing Video Games, Writing, Typing)

  • Frequent Use of Hand Tools (E.g., Screwdrivers, Scissors, or Paintbrushes)

  • Overuse From Racquet Sports (Tennis, Badminton, Squash, or Rock Climbing)

  • Holding Objects for Long Periods (Steering Wheel, Smartphones, Pens, Knitting Needles)

  • Wrist and Thumb Overuse in Musicians (Guitarists, Pianists, Drummers, Violinists)

  • Poor Ergonomics (Incorrect Keyboard and Mouse Positioning, Overuse of Thumb for Clicking or Scrolling)

Trigger Point Referral Pattern

Trigger points in the extensor pollicis longus and brevis refer pain to:

  • The thumb and wrist (Mistaken for De Quervain’s Tenosynovitis or Arthritis)

  • The outer forearm near the thumb side (Can Resemble Radial Nerve Compression or Tendinitis)

  • The base of the thumb (Mistaken for Carpal Tunnel Syndrome or Joint Pain)

Pain from these muscles is often confused with nerve compression, arthritis, or thumb tendinitis.

Differential Diagnosis

Extensor pollicis longus and brevis trigger points may be mistaken for:

  • De Quervain’s Tenosynovitis (Pain and Swelling Along the Thumb Side of the Wrist, Especially With Gripping or Lifting Movements)

  • Radial Nerve Entrapment (Pain, Weakness, or Numbness in the Forearm and Hand, Particularly Near the Thumb)

  • Carpal Tunnel Syndrome (Pain or Numbness in the Hand and Fingers, Particularly at Night)

  • Osteoarthritis of the Thumb (Joint Pain and Stiffness, Worse in the Morning)

  • Wrist Extensor Tendinitis (Pain and Stiffness in the Wrist and Forearm After Repetitive Use)

A thorough hand, wrist, and forearm examination is necessary to rule out these conditions.

Associated Trigger Points

Extensor pollicis longus and brevis trigger points often co-exist with:

  • Abductor Pollicis Longus (Pain in the Thumb and Wrist, Weak Pinching Ability)

  • Extensor Carpi Radialis Longus/Brevis (Forearm and Wrist Pain, Weak Grip Strength)

  • Brachioradialis (Pain Along the Forearm and Wrist, Affects Lifting Movements)

  • Flexor Pollicis Longus (Pain in the Palm and Thumb, Weak Thumb Flexion)

Anatomy and Innervation

Muscle Origin Insertion Innervation
Extensor Pollicis Longus Ulna, interosseous membrane Base of the distal phalanx of the thumb Radial nerve (C7–C8)
Extensor Pollicis Brevis Radius, interosseous membrane Base of the proximal phalanx of the thumb Radial nerve (C7–C8)

The EPL and EPB are innervated by the radial nerve, which also controls wrist and finger extensors.

Patient Examination

A comprehensive examination should include:

  • Palpation: Identify tender nodules along the forearm, near the wrist and thumb.

  • Resisted Thumb Extension Testing: Assess pain and weakness when lifting the thumb upward against resistance.

  • Grip Strength Testing: Determine if pain affects endurance when holding objects for long periods.

  • Radial Nerve Compression Testing: Rule out nerve-related causes of wrist and hand pain.

Corrective Actions

Manual Therapy

  • Trigger Point Release: Apply direct pressure to tight spots along the forearm and wrist extensors.

  • Massage Therapy: Helps improve circulation and reduce muscle tightness.

Stretching

  • Thumb Extension Stretch: Extend the arm with the palm facing down, gently pull the thumb away from the palm.

  • Forearm Rotation Stretch: Slowly rotate the wrist through pronation and supination to improve mobility.

Strengthening Exercises

  • Thumb Extension With Resistance Bands: Strengthens the extensor pollicis muscles and surrounding hand muscles.

  • Grip Strength Drills: Improves forearm endurance and function.

  • Eccentric Thumb Extension Exercises: Helps build strength while reducing tension.

Postural and Ergonomic Adjustments

  • Modify Keyboard and Mouse Positioning (Reduce Wrist Extension and Strain)

  • Use an Ergonomic Mouse or Wrist Support (Prevents Overuse Injuries)

  • Take Frequent Breaks During Repetitive Tasks (Allows Hand and Forearm Muscles to Recover)

➡️ Learn more about Trigger Points

Sources:

  • Travell, J. G., & Simons, D. G. (1983). Myofascial Pain and Dysfunction: The Trigger Point Manual (2nd ed.). Williams & Wilkins.

  • Simons, D., & Travell, J. (1999). The Trigger Point Manual, Volume 2: The Lower Extremities. Williams & Wilkins.