triceps surae muscle

{{short description|Pair of muscles: gastrocnemius and the soleus}}

{{Infobox muscle

| Name = Triceps surae

| Pronunciation = {{IPAc-en|ˈ|t|r|aɪ|s|ɛ|p|s|_|ˈ|sj|ʊər|i}}

| Latin = musculus triceps surae

| Image = Triceps surae.svg

| Caption = Posterior view of the triceps surae.

| Image2 = Triceps surae by Majid Doroudi.webm

| Caption2 = Dissection video (1 min 40 s)

| Origin = Distal femur (gastrocnemius), posterior tibia (soleus)

| Insertion = Achilles tendon, calcaneus

| Artery = Posterior tibial artery

| Nerve = Tibial nerve

| Action = Plantarflexion

| Antagonist =

}}

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.

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.{{cite journal | vauthors = Dixon JB | title = Gastrocnemius vs. soleus strain: how to differentiate and deal with calf muscle injuries | journal = Current Reviews in Musculoskeletal Medicine | volume = 2 | issue = 2 | pages = 74–7 | date = June 2009 | pmid = 19468870 | pmc = 2697334 | doi = 10.1007/s12178-009-9045-8 }}

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.{{cite journal | vauthors = Honeine JL, Schieppati M, Gagey O, Do MC | title = The functional role of the triceps surae muscle during human locomotion | journal = PLOS ONE | volume = 8 | issue = 1 | pages = e52943 | date = 2013-01-16 | pmid = 23341916 | pmc = 3547017 | doi = 10.1371/journal.pone.0052943 | doi-access = free }}

Clinical significance

= Calf strain (torn calf muscle) =

A calf strain refers to damage to a muscle or its attaching tendons.{{Cite web|url=https://physioworks.com.au/injuries-conditions-1/calf-muscle-tears|title=Calf Muscle Tear|website=physioworks.com.au|access-date=2020-02-09}} 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.{{cite news | url = https://aaptiv.com/magazine/stretches-for-runners|title=7 Pre- and Post-Workout Stretches for Runners – Aaptiv|date=2018-05-03|work=Aaptiv|access-date=2018-06-11 | first = McCall | last = Minnor | name-list-style = vanc }}

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.

File:Sobo 1909 304.png|Illustration of soleus.

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-soleus junction.

Etymology and pronunciation

The term is pronounced {{IPAc-en|ˈ|t|r|aɪ|s|ɛ|p|s|_|ˈ|sj|ʊər|i}}. It is from Latin caput and sura meaning "three-headed [muscle] of the calf".