What is triceps surae muscle?

Triceps Surae Muscle: Anatomy, Function, and Clinical Relevance

Introduction

The triceps surae is a powerful muscle group located in the posterior compartment of the leg. Comprising two major muscles—the gastrocnemius and soleus—this group plays a central role in plantarflexion of the foot at the ankle joint and is essential for walking, running, and jumping. Due to its crucial function and frequent involvement in athletic injuries and clinical conditions like tendinopathy, a thorough understanding of the triceps surae is vital for physiotherapists, sports medicine professionals, and clinicians alike.

Anatomy of Triceps Surae

Muscle Components

The triceps surae is composed of

1. Gastrocnemius muscle

   • Medial head

   • Lateral head

2. Soleus muscle

These muscles converge into a common tendon—the Achilles tendon—which inserts into the posterior surface of the calcaneus.

Origin and Insertion

Muscle	Origin	Insertion
Gastrocnemius	Medial head: posterior surface of the medial condyle of femur	Posterior calcaneus via Achilles tendon
	Lateral head: lateral surface of the lateral condyle of femur
Soleus	Posterior surface of the proximal fibula and soleal line of tibia	Posterior calcaneus via Achilles tendon

Nerve Supply

• Tibial nerve (S1–S2), a branch of the sciatic nerve, innervates both the gastrocnemius and soleus muscles.

Blood Supply

• Branches from the posterior tibial artery, peroneal artery, and popliteal artery supply the triceps surae.

Function of Triceps Surae

The triceps surae functions primarily as a plantarflexor of the ankle and plays a role in knee flexion (gastrocnemius only). Specific actions include

• Plantarflexion of the ankle during toe-off in walking and running.

• Stabilization of the leg during single-leg stance.

• Knee flexion (gastrocnemius crosses the knee joint).

Clinical Assessment

1. Palpation

• Palpation of the triceps surae is performed in the prone position with the foot hanging off the edge of the examination table.

• The gastrocnemius is superficial and easily palpated during resisted plantarflexion.

• The soleus, being deep, is better assessed when the knee is flexed, minimizing gastrocnemius involvement.

2. Power Testing

• Manual Muscle Testing (MMT): Ask the patient to stand on their toes. Repetitions and symmetry with the unaffected side are assessed.

• Alternatively, in a supine or seated position, resistance can be applied against plantarflexion.

3. Length Testing

• The Silfverskiöld Test differentiates between tightness in the gastrocnemius and soleus:

  • Limited dorsiflexion with the knee extended but normal with the knee flexed indicates a tight gastrocnemius.

  • Persistent limitation in both positions suggests soleus tightness.

Therapeutic Exercises

Stretching Exercises

1. Gastrocnemius Stretch

• Patient Position: Standing facing a wall.

• Procedure: Step back with one leg straight and heel flat on the ground, and lean forward.

• Hold for 30 seconds, 3 sets.

2. Soleus Stretch

• Patient Position: Same as above, but with the back leg slightly bent.

• Procedure: Lean in while keeping the heel down.

• Hold for 30 seconds, 3 sets.

Strengthening Exercises

1. Heel Raises (Double/Single Leg)

• Position: Standing near support.

• Procedure: Rise onto toes, hold for 2 seconds, and lower slowly.

• Progression: From double-leg to single-leg, add weights for advanced strengthening.

2. Seated Calf Raises

• Position: Seated with knees at 90°, weight over thighs.

• Procedure: Raise heels, pause, and slowly return.

Trigger Points

Common Sites

• Gastrocnemius: Upper third of both medial and lateral bellies.

• Soleus: Deep central part near mid-calf.

Symptoms

• Referred pain down the calf to the heel or plantar surface.

• Deep aching, stiffness, and tightness in the posterior leg.

Management

• Dry needling, myofascial release, and stretching can help deactivate trigger points.

Related Injuries and Conditions

1. Calf Strain

• Common in sports involving sudden acceleration.

• Usually affects the medial head of the gastrocnemius.

• Treatment: RICE, progressive loading, and physiotherapy.

2. Achilles Tendinopathy

• Overuse injury associated with degeneration of the Achilles tendon.

• Common in runners and jumpers.

• Managed with eccentric calf loading protocols and activity modification.

3. Compartment Syndrome

• Increased pressure within the posterior compartment can compromise circulation.

• Requires urgent assessment and potential surgical intervention.

Summary Table

Aspect	Description
Muscles Included	Gastrocnemius (2 heads), Soleus
Function	Plantarflexion, knee flexion (gastrocnemius)
Nerve Supply	Tibial nerve (S1–S2)
Clinical Relevance	Tendinopathy, strain, tightness, trigger points
Exercises	Heel raises, stretches (wall calf stretch, seated soleus stretch)

Conclusion

The triceps surae plays a central biomechanical role in locomotion and posture. Understanding its anatomy and function aids in diagnosing and managing lower limb injuries and dysfunctions. Proper assessment and intervention targeting the triceps surae can significantly improve patient outcomes in rehabilitation and athletic performance.

References

1. Physiopedia. Triceps Surae. https://www.physio-pedia.com/Triceps_Surae

2. Hoppenfeld, S. (1976). Physical Examination of the Spine and Extremities. Appleton-Century-Crofts.

3. Kendall, F. P., McCreary, E. K., Provance, P. G., Rodgers, M. M., & Romani, W. A. (2005). Muscles: Testing and Function with Posture and Pain. Lippincott Williams & Wilkins.

4. Neumann, D. A. (2010). Kinesiology of the Musculoskeletal System: Foundations for Rehabilitation. Elsevier Health Sciences.

5. Magee, D. J. (2014). Orthopedic Physical Assessment. Elsevier Health Sciences.