Calf (leg)
{{short description|Back part of lower leg}}
{{other uses|Calf (disambiguation)}}
{{Infobox anatomy
| Name = Calf
| Latin = sura
| Greek = acfle
| Image = Sb calf.png
| Caption = The calf is the back portion of the lower leg
| Image2 = File:Braus 1921 293.png
| Caption2 = Cross-section of lower right leg, through the calf, showing its 4 compartments: anterior at upper right; lateral at center right; deep posterior at center; superficial posterior at the bottom
| Precursor =
| System =
| Artery =
| Vein =
| Nerve =
| Lymph =
}}The calf ({{plural form}}: calves; Latin: sura) is the back portion of the lower leg in human anatomy.{{OED|calf|id=26331}} The muscles within the calf correspond to the posterior compartment of the leg. The two largest muscles within this compartment are known together as the calf muscle and attach to the heel via the Achilles tendon. Several other, smaller muscles attach to the knee, the ankle, and via long tendons to the toes.
Etymology
From Middle English calf, kalf, from Old Norse kalfi, possibly derived from the same Germanic root as English calf ("young cow"). Cognate with Icelandic kálfi ("calf of the leg").{{Cite web|url=https://en.wiktionary.org/wiki/calf|title=calf - Wiktionary|website=en.wiktionary.org|language=en|access-date=2020-03-22}} Calf and calf of the leg are documented in use in Middle English circa AD 1350 and AD 1425 respectively.{{cite book|author=Hans Kurath|url=https://books.google.com/books?id=gjbI9cRavYoC&pg=PA20|title=Middle English dictionary|publisher=University of Michigan Press|year=1959|isbn=978-0-472-01031-8|pages=128}} page 20
Historically, the absence of calf, meaning a lower leg without a prominent calf muscle, was regarded by some authors as a sign of inferiority: it is well known that monkeys have no calves, and still less do they exist among the lower orders of mammals.{{cite book|author=Maria Montessori|url=https://archive.org/details/pedagogicalanthr00mont|title=Pedagogical anthropology|publisher=Frederick A. Stokes Company|others=Frederic Taber Cooper|year=1913|pages=[https://archive.org/details/pedagogicalanthr00mont/page/n571 508]|author1-link=Maria Montessori}} page 311
Structure
{{expand section|date=February 2014}}
The calf is composed of the muscles of the posterior compartment of the leg: The gastrocnemius and soleus (composing the triceps surae muscle) and the tibialis posterior. The sural nerve provides innervation.
Clinical significance
Medical conditions that result in calf swelling among other symptoms include deep vein thrombosis{{cite book| title = The rational clinical examination: Evidence-based clinical diagnosis| author = David Simel| author2 = Drummond Rennie| author3 = Robert Hayward| author4 = Sheri A Keitz| publisher = McGraw-Hill Professional| year = 2008| isbn = 978-0-07-159030-3| url = https://books.google.com/books?id=Xs2tePzm_O0C| pages = 500
}} page 229 compartment syndrome,{{cite journal| vauthors = Drey IA, Baruch H| title = Acute compartment syndrome of the calf presenting after prolonged decubitus position| journal = Orthopedics| volume = 31| issue = 2| pages = 184| date = February 2008| pmid = 19292184| doi = 10.3928/01477447-20080201-08
}} Achilles tendon rupture, and varicose veins.
Idiopathic leg cramps are common and typically affect the calf muscles at night.{{cite journal| author = Young G| title = Leg cramps| journal = Clinical Evidence| volume = 2009| year = 2009| pmid = 19445755| pmc = 2907778
}} Edema also is common and in many cases idiopathic. In a small study of factory workers in good health, wearing compression garments helped to reduce edema and the pain associated with edema.{{cite journal| vauthors = Blättler W, Kreis N, Lun B, Winiger J, Amsler F| title = Leg symptoms of healthy people and their treatment with compression hosiery| journal = Phlebology| volume = 23| issue = 5| pages = 214–21| year = 2008| pmid = 18806203| doi = 10.1258/phleb.2008.008014
| s2cid = 23827067}} A small study of runners found that wearing knee-high compression stockings while running significantly improved performance.{{cite journal| vauthors = Kemmler W, von Stengel S, Köckritz C, Mayhew J, Wassermann A, Zapf J| title = Effect of compression stockings on running performance in men runners| journal = Journal of Strength and Conditioning Research| volume = 23| issue = 1| pages = 101–5| date = January 2009| pmid = 19057400| doi = 10.1519/JSC.0b013e31818eaef3
| s2cid = 5809442| doi-access = free}}
The circumference of the calf has been used to estimate selected health risks. In Spain, a study of 22,000 persons 65 or older found that a smaller calf circumference was associated with a higher risk of undernutrition.{{cite journal| vauthors = Cuervo M, Ansorena D, García A, González Martínez MA, Astiasarán I, Martínez JA| title = [Assessment of calf circumference as an indicator of the risk for hyponutrition in the elderly]| language = es| journal = Nutrición Hospitalaria | volume = 24| issue = 1| pages = 63–7| year = 2009| pmid = 19266115
}} In France, a study of 6265 persons 65 or older found an inverse correlation between calf circumference and carotid plaques.{{cite journal| vauthors = Debette S, Leone N, Courbon D, Gariépy J, Tzourio C, Dartigues JF, Ritchie K, Alpérovitch A, Ducimetière P, Amouyel P, Zureik M| title = Calf circumference is inversely associated with carotid plaques| journal = Stroke: A Journal of Cerebral Circulation| volume = 39| issue = 11| pages = 2958–65| date = November 2008| pmid = 18703804| doi = 10.1161/STROKEAHA.108.520106| url =http://hal.archives-ouvertes.fr/docs/00/27/15/21/PDF/Mollet_Stroke_08.pdf
| doi-access = free}}
Calf augmentation and restoration is available, using a range of prosthesis devices and surgical techniques.
Training and Exercise
The calves can be isolated by performing movements involving plantarflexion (pointing the toes down). The two major categories of calf exercises are those that maintain an extended knee, and those that maintain a flexed knee.
The first category includes movements such as standing calf raises, donkey calf raises and stair calves. The second category includes movements that maintain a bent knee, such as seated calf raises. Movements with a straight knee will target the gastrocnemius muscle more, and movements with a bent-knee will target the soleus muscle more. However, both variations will target both muscles to a large degree.
It is important to train the calves relatively close to failure, which is 0-4 repetitions away from technical failure. They recover quickly, often requiring rest times of as little as 10 seconds and often no more than 60 seconds. Ensuring a 1-2 second pause at the top and bottom of the movement will put more emphasis on the muscle, and less emphasis on the achilles tendon.