Triceps surae muscle

The triceps surae consists of two muscles located at the calf – the two-headed gastrocnemius and the soleus. These muscles both insert into the calcaneus, the bone of the heel of the human foot, and form the major part of the muscle of the posterior leg, commonly known as the calf muscle.

Triceps surae
Posterior view of the triceps surae.
Dissection video (1 min 40 s)
Details
Pronunciation	/ˈtraɪsɛps ˈsjʊəri/
Origin	Distal femur (gastrocnemius), posterior tibia (soleus)
Insertion	Achilles tendon, calcaneus
Artery	Posterior tibial artery
Nerve	Tibial nerve
Actions	Plantarflexion
Identifiers
Latin	musculus triceps surae
TA98	A04.7.02.043
TA2	2656
FMA	51062
Anatomical terms of muscle

Structure

The triceps surae is connected to the foot through the Achilles tendon, and has three heads deriving from the two major masses of muscle.

• The superficial portion (the gastrocnemius) gives off two heads attaching to the base of the femur directly above the knee.
• The deep (profundus) mass of muscle (the soleus) forms the remaining head which attaches to the superior posterior area of the tibia.

The triceps surae is innervated by the tibial nerve, specifically, nerve roots L5–S2.

Function

Contraction of the triceps surae induce plantar flexion (sagittal plane) and stabilization of the ankle complex in the transverse plane. Functional activities include primarily movement in the sagittal plane, stabilization during locomotion (walking, running), restraining the body from falling and power jumping. By controlling the disequilibrium torque, the triceps surae can affect force through the exchange of potential into kinetic energy.

Clinical significance

Calf strain (torn calf muscle)

A calf strain refers to damage to a muscle or its attaching tendons. A premature return before recovery is achieved will result in a prolonged recovery or incomplete return to baseline prior to injury. Stretches such as alternating calf raises can improve flexibility as well as mobilize legs before running.

Calf muscles are a common place for fasciculations.

Additional images

• 
  Animation. Gastrocnemius and soleus are shown in different colors.
• 
  Illustration of the gastrocnemius.
• 
  Illustration of soleus.
• 
  Nerves, arteries and veins surround the gastrocnemius and soleus.
• 
  Cross section of the lower leg, with triceps surae at back (soleus and gastrocnemius)
• 
  Nerves and blood-vessels overlying the triceps surae
• 
  Photograph of the gastrocnemius-soleus junction.

Etymology and pronunciation

The term is pronounced /ˈtraɪsɛps ˈsjʊəri/. It is from Latin caput and sura meaning "three-headed [muscle] of the calf".

Further reading

• McCarthy JP, Hunter GR, Larson-Meyer DE, Bamman MM, Landers KA, Newcomer BR (August 2006). "Ethnic differences in triceps surae muscle-tendon complex and walking economy". Journal of Strength and Conditioning Research. 20 (3): 511–8. doi:10.1519/17395.1. PMID 16937962. S2CID 23097795.