Flexor Carpi Ulnaris Trigger Points

Introduction

The flexor carpi ulnaris (FCU) is a key forearm muscle responsible for wrist flexion and ulnar deviation. When trigger points develop in this muscle, they can cause pain in the wrist, forearm, and pinky side of the hand, often mimicking ulnar nerve entrapment, carpal tunnel syndrome, or wrist tendinitis.

Name and Area

  • Name: Flexor Carpi Ulnaris (FCU)

  • Area: Located on the medial forearm, running from the humerus and ulna to the base of the fifth metacarpal and pisiform bone.

Indications

Flexor carpi ulnaris trigger points may contribute to:

  • Pain on the Inner Forearm and Wrist (Mistaken for Ulnar Nerve Compression or Wrist Arthritis)

  • Pain That Radiates to the Pinky Side of the Hand (Can Mimic Carpal Tunnel or Tendinitis)

  • Weakness in Wrist Flexion (Difficulty Holding Objects, Writing, or Typing)

  • Pain When Gripping or Bending the Wrist Forward (Common in Golfers, Tennis Players, and Weightlifters)

  • Forearm Fatigue or Cramping with Repetitive Use (E.g., Playing an Instrument, Driving, Knitting, Cooking)

  • Pain That Worsens with Wrist Movements (E.g., Typing, Carrying Bags, Holding a Steering Wheel)

Pain from this muscle is often mistaken for ulnar nerve entrapment, arthritis, or wrist tendinitis.

Muscle Action

  • Flexes the Wrist: Moves the hand toward the palm.

  • Assists in Ulnar Deviation: Moves the wrist slightly toward the pinky side.

  • Provides Wrist Stability: Works with other flexor and extensor muscles to support grip strength.

The FCU is essential for gripping, wrist stabilization, and fine motor tasks.

Signs and Symptoms

Individuals with flexor carpi ulnaris trigger points often report:

  • Pain on the Inner Forearm and Wrist, Especially on the Pinky Side

  • Difficulty Bending the Wrist Forward (Pain When Typing, Writing, or Using a Mouse)

  • Weakness in Grip Strength (Difficulty Holding a Golf Club, Tennis Racket, or Opening Jars)

  • Pain That Worsens with Repetitive Hand and Wrist Movements (E.g., Playing Tennis, Texting, Playing an Instrument)

  • Burning or Aching Sensation in the Forearm (Can Be Mistaken for Nerve Pain or Tendinitis)

Pain worsens with repetitive gripping, wrist flexion, or prolonged forearm use.

Perpetuating Factors

Common causes of flexor carpi ulnaris trigger points include:

  • Repetitive Wrist Flexion Movements (Typing, Gaming, Playing Instruments, Writing, Weightlifting, Rock Climbing)

  • Frequent Use of a Computer Mouse or Touchscreen Devices (Sustained Wrist Flexion Without Support)

  • Prolonged Hand Grip or Holding Objects for Extended Periods (Driving, Holding a Phone, Steering Wheel Grip, Cooking)

  • Overuse in Racquet Sports (Tennis, Badminton, Squash, or Golf)

  • Poor Ergonomics (Awkward Wrist Position While Using a Keyboard, Phone, or Mouse)

Trigger Point Referral Pattern

Trigger points in the flexor carpi ulnaris refer pain to:

  • The inner forearm and wrist (Mistaken for Wrist Tendinitis or Ulnar Nerve Entrapment)

  • The pinky side of the hand and wrist (Can Resemble Carpal Tunnel or Arthritis)

  • The elbow joint (Mistaken for Golfer’s Elbow or Ligament Sprains)

Pain from this muscle is often confused with wrist arthritis, carpal tunnel syndrome, or overuse injuries.

Differential Diagnosis

Flexor carpi ulnaris trigger points may be mistaken for:

  • Ulnar Nerve Compression (Pain, Numbness, and Tingling in the Pinky Side of the Hand and Forearm)

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

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

  • Golfer’s Elbow (Medial Epicondylitis – Inner Elbow Pain That Affects the Wrist and Hand)

  • Osteoarthritis or Rheumatoid Arthritis (Pain and Stiffness in the Wrist Joints, Especially in the Morning)

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

Associated Trigger Points

Flexor carpi ulnaris trigger points often co-exist with:

  • Flexor Digitorum Superficialis (Pain in the Palm and Fingers, Weak Grip Strength)

  • Flexor Carpi Radialis (Pain on the Inner Wrist and Hand, Affects Grip Strength)

  • Pronator Teres (Pain in the Forearm and Wrist, Weakness in Forearm Rotation)

  • Extensor Carpi Ulnaris (Pain in the Outer Forearm and Wrist, Weak Grip Strength)

Anatomy and Innervation

Muscle Origin Insertion Innervation
Flexor Carpi Ulnaris Medial epicondyle of humerus, olecranon of ulna Pisiform bone, hamate, base of the fifth metacarpal Ulnar nerve (C7–T1)

The FCU is innervated by the ulnar nerve, which also controls grip strength and pinky-side wrist movement.

Patient Examination

A comprehensive examination should include:

  • Palpation: Identify tender nodules along the forearm, near the wrist and pinky-side of the hand.

  • Resisted Wrist Flexion Testing: Assess pain and weakness when bending the wrist forward against resistance.

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

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

Corrective Actions

Dry Needling

  • Dry needling can release trigger points in the flexor carpi ulnaris, reducing muscle tightness and improving mobility.

Manual Therapy

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

  • Massage Therapy: Helps improve circulation and reduce forearm tension.

Stretching

  • Wrist Flexor Stretch: Extend the arm with the palm facing upward, gently pull the fingers toward the body.

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

Strengthening Exercises

  • Wrist Flexion with Resistance Bands: Strengthens the flexor carpi ulnaris and surrounding hand muscles.

  • Grip Strength Drills: Improves forearm endurance and function.

  • Eccentric Wrist Flexion Exercises: Helps build strength while reducing tension.

Postural and Ergonomic Adjustments

  • Modify Keyboard and Mouse Positioning (Reduce Wrist Flexion 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)

Conclusion

The flexor carpi ulnaris plays a crucial role in wrist flexion and grip strength, but trigger points in this muscle can cause significant wrist, forearm, and hand pain. By incorporating dry needling, manual therapy, stretching, and strengthening exercises, individuals can reduce pain, improve mobility, and prevent future dysfunction.

➡️ 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.