The triceps surae consists of two
muscles located at the
calf – the two-headed
gastrocnemius
The gastrocnemius muscle (plural ''gastrocnemii'') is a superficial two-headed muscle that is in the back part of the lower leg of humans. It runs from its two heads just above the knee to the heel, a three joint muscle (knee, ankle and subtalar ...
and the
soleus
In humans and some other mammals, the soleus is a powerful muscle in the back part of the lower leg (the calf). It runs from just below the knee to the heel, and is involved in standing and walking. It is closely connected to the gastrocnemius mu ...
. 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 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 (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
The tibial nerve is a branch of the sciatic nerve. The tibial nerve passes through the popliteal fossa to pass below the arch of soleus.
Structure Popliteal fossa
The tibial nerve is the larger terminal branch of the sciatic nerve with root val ...
, 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
The sagittal plane (; also known as the longitudinal plane) is an anatomical plane that divides the body into right and left sections. It is perpendicular to the transverse and coronal planes. The plane may be in the center of the body and div ...
, stabilization during locomotion (walking, running), restraining the body from falling and power
jumping
Jumping or leaping is a form of locomotion or movement in which an organism or non-living (e.g., robotics, robotic) mechanical system propels itself through the air along a ballistic trajectory. Jumping can be distinguished from running, gallo ...
. 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
Strain may refer to:
Science and technology
* Strain (biology), variants of plants, viruses or bacteria; or an inbred animal used for experimental purposes
* Strain (chemistry), a chemical stress of a molecule
* Strain (injury), an injury to a mu ...
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
Stiffness is the extent to which an object resists deformation in response to an applied force.
The complementary concept is flexibility or pliability: the more flexible an object is, the less stiff it is.
Calculations
The stiffness, k, of a bo ...
as well as mobilize legs before running.
Calf muscles are a common place for
fasciculations.
Additional images
File:Triceps surae - animation.gif, Animation. Gastrocnemius and Soleus are shown in different colors.
File:Sobo 1909 303.png, Illustration of the gastrocnemius
The gastrocnemius muscle (plural ''gastrocnemii'') is a superficial two-headed muscle that is in the back part of the lower leg of humans. It runs from its two heads just above the knee to the heel, a three joint muscle (knee, ankle and subtalar ...
.
File:Sobo 1909 304.png, Illustration of soleus
In humans and some other mammals, the soleus is a powerful muscle in the back part of the lower leg (the calf). It runs from just below the knee to the heel, and is involved in standing and walking. It is closely connected to the gastrocnemius mu ...
.
File:Sobo 1909 579-580.png, Nerves, arteries and veins surround the gastrocnemius and soleus.
File:Braus 1921 293.png, Cross section of the lower leg, with triceps surae at back (soleus and gastrocnemius)
File:Sobo_1909_720.png, Nerves and blood-vessels overlying the triceps surae
File:Medial view of a cadaver dissection of the gastrocnemius–soleus junction - with text.png, Photograph of the gastrocnemius
The gastrocnemius muscle (plural ''gastrocnemii'') is a superficial two-headed muscle that is in the back part of the lower leg of humans. It runs from its two heads just above the knee to the heel, a three joint muscle (knee, ankle and subtalar ...
-soleus
In humans and some other mammals, the soleus is a powerful muscle in the back part of the lower leg (the calf). It runs from just below the knee to the heel, and is involved in standing and walking. It is closely connected to the gastrocnemius mu ...
junction.
Etymology and pronunciation
The term is pronounced . It is from Latin ''caput'' and ''sura'' meaning "three-headed
uscleof the calf".
References
Further reading
*
{{Authority control
Calf muscles
Muscles of the lower limb