Gastrocnemius - Muscle Physiology & Functional Anatomy

Anatomy

Origin:

• Lateral head:

  • Posterior surface of lateral condyle of femur & highest of three facets on lateral condyle
    

• Medial head

  • Posterior medial condyle of femur (posterior surface of femur above medial condyle)
    
    

Insertion

• Achilles Tendon (calcaneus to middle of three facets on posterior aspect of calcaneus)
  

Major Arteries:

• Sural arteries

Neural Innervation:

• Tibial nerve (S1-S2)

Trigger Points: 

Physiology

Concentric Functions:

• Flexion of the knee (primarily during swing phase of gait)

• Plantarflexion of the ankle

• Subtalar joint supination (at the end of mid-stance)
  

Eccentric Functions:

• Decelerates ankle dorsiflexion

• Decelerates femoral internal rotation

• Decelerates subtalar joint pronation
  

Isometric Function:

• Helps stabilize the foot & ankle complex

• Helps stabilize the subtalar joint & tibio-femoral joint during transitional movements

Related Muscles

• Soleus

Antagonist:

• Quadriceps (leg extension)

  • Rectus Femoris
  • Vastus Lateralis
  • Vastus Medialis
  • Vastus Intermedius
• Tibialis Anterior (dorsiflexion)

Exercises:

More Images of the Gastrocnemius Muscle

More Information about the Gastrocnemius Muscle

The gastrocnemius muscle is a biarticulate muscle which means it has functions over 2 joints in this case the knee & the ankle.  lThe gastrocnemius is named after the the Greek words "gaster" which means stomach & "knēmē" which means leg.  The literal meaning "stomach of leg" is due to the bulging shape of the calf muscles.

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