Interossei of the Foot Trigger Points

Introduction

The interossei muscles of the foot are small but crucial muscles that control toe movement, foot stability, and balance. When trigger points develop in these muscles, they can cause pain in the toes, forefoot, and arch, often mimicking Morton’s neuroma, metatarsalgia, or nerve entrapment.

Name and Area

  • Name: Interossei of the Foot (Plantar and Dorsal Interossei)

  • Area: Located between the metatarsal bones, spanning from the metatarsals to the proximal phalanges of toes 2–5.

Indications

Interossei trigger points may contribute to:

  • Pain in the Toes and Forefoot (Mistaken for Morton’s Neuroma or Metatarsalgia)

  • Pain That Extends to the Ball of the Foot (Can Mimic Capsulitis or Sesamoiditis)

  • Toe Cramping or Stiffness (Especially with Walking or Running)

  • Pain When Spreading or Curling the Toes (Common in Athletes, Dancers, and Runners)

  • Discomfort When Walking Barefoot on Hard Surfaces

  • Pain That Worsens with Tight Shoes or High Heels

Pain from these muscles is often mistaken for nerve entrapment, arthritis, or toe joint dysfunction.

Muscle Action

  • Dorsal Interossei:

    • Abduct the Toes: Move toes away from the midline.

    • Assist in Toe Flexion and Extension: Help stabilize the foot during walking and running.

  • Plantar Interossei:

    • Adduct the Toes: Move toes toward the midline.

    • Assist in Balance and Foot Stabilization.

The interossei muscles are essential for foot dexterity, balance, and toe coordination.

Signs and Symptoms

Individuals with interossei trigger points often report:

  • Pain Between the Toes or on the Top of the Foot (Can Mimic Morton’s Neuroma or Arthritis)

  • Pain When Spreading the Toes or Pressing on the Ball of the Foot

  • Toe Cramping or Stiffness After Activity (Common in Runners and Dancers)

  • Pain That Worsens with Narrow or Tight Shoes (Feels Like a Pinching Sensation Between the Toes)

  • Burning or Tingling in the Toes (Mistaken for Nerve Compression or Neuropathy)

Pain worsens with prolonged standing, walking, or wearing restrictive footwear.

Perpetuating Factors

Common causes of interossei trigger points include:

  • Wearing Tight or Narrow Shoes (E.g., High Heels, Cleats, or Dress Shoes)

  • Overuse From Running, Sprinting, or Jumping

  • Foot Instability Due to High Arches or Flat Feet

  • Walking or Standing for Long Periods on Hard Surfaces

  • Toe-Curling Movements or Foot Strain from Certain Sports (Dancing, Ballet, or Soccer)

Trigger Point Referral Pattern

Trigger points in the interossei muscles refer pain to:

  • The forefoot and toes (Mistaken for Morton’s Neuroma or Metatarsalgia)

  • The ball of the foot (Can Resemble Capsulitis or Joint Pain)

  • The top of the foot (Mistaken for Nerve Pain or Tendinitis)

Pain from these muscles is often confused with nerve entrapment, metatarsalgia, or sesamoiditis.

Differential Diagnosis

Interossei trigger points may be mistaken for:

  • Morton’s Neuroma (Pain and Numbness Between the Toes, Often Worse in Tight Shoes)

  • Metatarsalgia (Pain in the Ball of the Foot, Worsens with Walking or Running)

  • Capsulitis (Inflammation in the Toe Joints, Causes Swelling and Tenderness)

  • Tarsal Tunnel Syndrome (Burning Pain and Numbness in the Foot and Toes)

  • Plantar Plate Tear (Pain at the Base of the Toes, Often Due to Overuse or Hyperextension)

A thorough foot and toe examination is necessary to rule out these conditions.

Associated Trigger Points

Interossei trigger points often co-exist with:

  • Flexor Digitorum Brevis (Pain in the Arch and Toes, Affects Foot Stability and Push-Off Strength)

  • Extensor Digitorum Longus (Top of Foot and Toe Pain, Affects Toe Extension and Balance)

  • Tibialis Posterior (Pain Along the Inner Ankle and Foot, Affects Arch Support and Stability)

  • Peroneus Longus and Brevis (Lateral Foot and Ankle Pain, Can Affect Balance and Gait)

Anatomy and Innervation

Muscle Origin Insertion Innervation
Dorsal Interossei Adjacent sides of metatarsals 1–5 Proximal phalanges of toes 2–4 Lateral plantar nerve (S2–S3)
Plantar Interossei Medial sides of metatarsals 3–5 Medial bases of proximal phalanges of toes 3–5 Lateral plantar nerve (S2–S3)

The interossei muscles are innervated by the lateral plantar nerve, which also controls toe movement and foot stability.

Patient Examination

A comprehensive examination should include:

  • Palpation: Identify tender nodules along the metatarsal spaces and forefoot.

  • Toe Abduction and Adduction Strength Testing: Assess pain and weakness when spreading the toes outward or squeezing them together.

  • Gait Analysis: Look for abnormal foot movement patterns while walking or running.

  • Footwear Assessment: Determine if improper shoes are contributing to symptoms.

Corrective Actions

Dry Needling

  • Dry needling can release trigger points in the interossei muscles, reducing foot pain and improving toe mobility.

Manual Therapy

  • Trigger Point Release: Apply direct pressure to tight spots between the metatarsals and toes.

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

Stretching

  • Toe Spreading Stretch: Use toe separators or actively spread the toes apart to relieve tightness.

  • Foot Arch Stretch: Roll a tennis ball or massage ball under the foot to loosen tight muscles.

Strengthening Exercises

  • Toe Gripping Exercises: Strengthens the interossei and foot stabilizers.

  • Resistance Band Toe Movements: Improves toe control and foot endurance.

  • Short Foot Exercise: Helps activate the arch and improve foot stability.

Postural and Footwear Adjustments

  • Wear Wide Toe Box Shoes to Allow Natural Toe Movement

  • Use Custom Orthotics to Improve Foot Alignment

  • Avoid Excessive Barefoot Walking on Hard Surfaces

Conclusion

The interossei muscles of the foot play a crucial role in toe control, foot stability, and balance, but trigger points in these muscles can cause significant toe, forefoot, and arch 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.