Plantaris Trigger Points
Introduction
The plantaris is a small but important lower leg muscle responsible for assisting in ankle plantarflexion and knee flexion. When trigger points develop in this muscle, they can cause calf pain, Achilles discomfort, and knee tightness, often mimicking Achilles tendinitis, calf strain, or deep vein thrombosis (DVT).
Name and Area
Name: Plantaris
Area: Located in the posterior lower leg, running from the lateral femur to the Achilles tendon and calcaneus (heel bone).
Indications
Plantaris trigger points may contribute to:
Pain in the Back of the Knee and Calf (Mistaken for Gastrocnemius Strain or Baker’s Cyst)
Pain That Extends to the Achilles Tendon (Can Mimic Achilles Tendinitis or Soleus Dysfunction)
Tightness or Cramps in the Calf After Running or Walking
Pain or Stiffness in the Lower Leg When Stretching the Calf
Feeling of a "Tugging" Sensation Behind the Knee (Can Resemble Hamstring or Popliteal Pain)
Pain That Worsens with Running, Jumping, or Sudden Sprinting Movements
Pain from this muscle is often mistaken for Achilles tendinitis, calf strain, or deep vein thrombosis (DVT).
Muscle Action
Assists in Plantarflexion: Helps point the foot downward, aiding in walking and running.
Assists in Knee Flexion: Works with other lower leg muscles to bend the knee.
The plantaris is important for ankle function, knee stability, and explosive lower leg movements.
Signs and Symptoms
Individuals with plantaris trigger points often report:
Pain Along the Back of the Knee and Calf That Feels Like a Tight Band
Pain That Extends to the Achilles Tendon or Heel (Common in Runners and Sprinters)
Tightness or Cramping in the Calf After Activity or Prolonged Standing
Pain When Stretching the Calf or Pushing Off the Toes
A "Tugging" Sensation in the Posterior Knee When Extending the Leg
Pain That Worsens with Running, Jumping, or Sprinting Movements
Pain worsens with explosive lower leg activity, prolonged standing, or improper footwear.
Perpetuating Factors
Common causes of plantaris trigger points include:
Sudden Acceleration or Sprinting (Overloads the Calf and Achilles Complex)
Frequent Jumping Movements (Basketball, Tennis, Track and Field, or Dance)
Tight Calf Muscles (Forces the Plantaris to Work Harder for Foot and Knee Motion)
Wearing High Heels or Shoes with Poor Heel Support (Increases Achilles and Calf Strain)
Overuse in Runners and Long-Distance Walkers (Leads to Chronic Tension in the Posterior Leg Muscles)
Trigger Point Referral Pattern
Trigger points in the plantaris refer pain to:
The back of the knee and upper calf (Mistaken for Gastrocnemius Strain or Popliteal Pain)
The Achilles tendon and lower calf (Can Mimic Achilles Tendinitis or Soleus Tightness)
The heel and foot arch (Mistaken for Plantar Fasciitis or Posterior Tibial Dysfunction)
Pain from this muscle is often confused with Achilles tendinitis, calf strain, or nerve irritation.
Differential Diagnosis
Plantaris trigger points may be mistaken for:
Achilles Tendinitis (Pain and Stiffness in the Achilles Tendon, Worsens with Activity or Morning Steps)
Calf Strain (Sharp or Aching Pain in the Calf, Common in Runners and Jumping Athletes)
Baker’s Cyst (Swelling Behind the Knee, Can Cause Pain and Stiffness When Bending the Leg)
Deep Vein Thrombosis (DVT) (Pain, Swelling, and Warmth in the Calf, Requires Immediate Medical Attention)
Plantar Fasciitis (Heel Pain That Worsens with the First Steps in the Morning, Often Due to Foot Arch Dysfunction)
A thorough knee, ankle, and lower leg examination is necessary to rule out these conditions.
Associated Trigger Points
Plantaris trigger points often co-exist with:
Gastrocnemius (Calf and Achilles Pain, Affects Ankle Stability and Running Mechanics)
Soleus (Deep Calf and Achilles Pain, Common in Runners and Walkers)
Popliteus (Posterior Knee Pain, Can Affect Knee Stability and Leg Extension)
Tibialis Posterior (Inner Ankle and Foot Pain, Affects Arch Support and Stability)
Anatomy and Innervation
Muscle | Origin | Insertion | Innervation |
---|---|---|---|
Plantaris | Lateral supracondylar ridge of femur | Posterior calcaneus (via Achilles tendon) | Tibial nerve (S1–S2) |
The plantaris is innervated by the tibial nerve, which also controls foot and lower leg stability.
Patient Examination
A comprehensive examination should include:
Palpation: Identify tender nodules along the posterior knee and upper calf.
Resisted Plantarflexion and Knee Flexion Testing: Assess pain and weakness when pushing the foot downward and bending the knee.
Gait Analysis: Look for foot instability, excessive heel strike, or altered stride mechanics.
Ankle and Knee Stability Testing: Rule out ligament sprains, Achilles injuries, or nerve compression.
Corrective Actions
Dry Needling
Dry needling can release trigger points in the plantaris, reducing calf tightness and improving knee mobility.
Manual Therapy
Trigger Point Release: Apply deep sustained pressure to tight spots along the posterior knee and calf.
Massage Therapy: Helps improve circulation and reduce muscle tension in the lower leg.
Stretching
Calf Stretch on a Wall: Stand with one foot behind the other and lean forward to stretch the plantaris and calf.
Toe Extension Stretch: Gently pull the toes upward to relieve tension in the Achilles and plantar fascia.
Strengthening Exercises
Heel Raises: Strengthens the plantaris and calf muscles for better foot and knee control.
Single-Leg Balance Drills: Improves ankle proprioception and knee stability.
Eccentric Heel Drops: Helps improve flexibility and prevent Achilles-related dysfunction.
Postural and Footwear Adjustments
Avoid Wearing High Heels for Long Periods (Reduces Excessive Strain on the Achilles and Calf Muscles)
Use Proper Running Shoes with Heel Support (Prevents Overuse of the Plantaris and Peroneal Muscles)
Gradually Increase Running or Jumping Intensity (Prevents Sudden Overuse of the Plantaris)
Conclusion
The plantaris plays a crucial role in knee flexion, ankle plantarflexion, and lower leg function, but trigger points in this muscle can cause significant posterior knee, calf, and Achilles pain. By incorporating dry needling, manual therapy, stretching, and strengthening exercises, individuals can reduce pain, improve mobility, and prevent chronic lower leg dysfunction.
➡️ Learn more about Trigger Points
➡️ Explore our Trigger Point Index
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.