Triceps surae muscle

The triceps surae (/ˈtraɪsɛps ˈsjʊəriː/) (from Latin caput and sura. "three-headed [muscle] of the calf") is a pair of 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.

Structure

The two muscle layers that make up the triceps surae, namely the gastrocnemius and soleus.

The triceps surae is connected to the foot through the Achilles tendon, and has 3 heads deriving from the 2 major masses of muscle.

• The superficial portion (the gastrocnemius) gives off 2 heads attaching to the base of the femur directly above the knee.
• The deep (profundis) 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) and power jumping.

Clinical significance

Calf strain (torn calf muscle)

A torn calf muscle occurs when the calf muscle is pulled apart from the Achilles tendon. Severe pain is often felt by the victim and is often, but not always, accompanied by a "pop."

This injury happens during acceleration or changes in direction. The torn calf muscle may spasm, and contract forcefully. The toes may also point down. Bruises can show up in the leg, foot and ankle due to pooling of blood from internal bleeding. It may take some time for the bruises to occur, from hours to days depending upon where the tear occurred. The circumference of the leg will likely increase. This injury may take several months to heal.

Calf muscles are also very suspectable to Fasciculations and people with Benign Fasciculation syndrome often complain of twitching in either one or both calves.

Additional images

• 
  Nerves, arteries and veins surround the gastrocnemius and soleus.
• 
  Cross section of the lower leg, with triceps surae at back (soleus and gastrocnemius)
• 
  Lateral view of the lower leg with muscle visible
• 
  Nerves and blood-vessels overlying the triceps surae

External links

Wikimedia Commons has media related to Triceps surae muscle.

• McCarthy, John P.; Hunter, Gary R.; Larson-Meyer, D. Enette; Bamman, Marcas M.; Landers, Kathleen A.; Newcomer, Bradley R. (2006). "Ethnic Differences in Triceps Surae Muscle-Tendon Complex and Walking Economy". The Journal of Strength and Conditioning Research. 20 (3): 511–8. doi:10.1519/17395.1. PMID 16937962.