WordNet

make ones way by force; "He muscled his way into the office"
animal tissue consisting predominantly of contractile cells (同)muscular_tissue
one of the contractile organs of the body (同)musculus
authority or power or force (especially when used in a coercive way); "the senators used their muscle to get the party leader to resign"
the muscle in the back part of the leg that forms the greater part of the calf; responsible for the plantar flexion of the foot (同)gastrocnemius_muscle

PrepTutorEJDIC

〈U〉(動物体の組織としての)『筋肉』,筋(きん);〈C〉(体の各部を動かす)筋肉 / 〈U〉力,(特に)筋力,腕力 / 《俗に》(…に)強引に割り込む《+『in on』(『into, through』)+『名』》
筋肉の,筋力のある / 力ずくの

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2014/11/02 14:37:43」(JST)

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In humans, the gastrocnemius muscle (/ˌɡæstrɒkˈniːmiəs/ or /ˌɡæstrəkˈniːmiəs/; plural gastrocnemii; Latin, from Greek γαστήρ "stomach" and κνήμη (knēmē) "leg"; meaning "stomach of leg", referring to the bulging shape of the calf) is a very powerful superficial bipennate muscle that is in the back part of the lower leg. It runs from its two heads just above the knee to the heel.

Structure

The gastrocnemius is located with the soleus in the posterior (back) compartment of the leg. The lateral head originates from the lateral condyle of the femur, while the medial head originates from the medial condyle of the femur. Its other end forms a common tendon with the soleus muscle; this tendon is known as the calcaneal tendon or Achilles Tendon and inserts onto the posterior surface of the calcaneus, or heel bone.

Deep to the gastrocnemius (farther from the skin) is the soleus muscle. Some anatomists consider both to be a single muscle, the triceps surae or "calf muscle", since they share a common insertion via the Achilles tendon. The plantaris muscle and a portion of its tendon run between the two muscles, which is involved in "locking" the knee from the standing position. Since the anterior compartment of the leg is lateral to the tibia, the bulge of muscle medial to the tibia on the anterior side is actually the posterior compartment. The soleus is superficial to the mid-shaft of the tibia.

Variation

10% to 30% of individuals have a sesamoid bone called the "fabella" in the lateral head of gastrocnemius muscle.

Function

The gastrocnemius is primarily involved in running, jumping and other "fast" movements of leg, while to a lesser degree involved in walking and standing. This is due to the large degree of white muscle fibers present in the gastrocnemius. This is as opposed to the soleus, which has a larger degree of red muscle fibers and is the primarily activated muscle during the action of standing still, as has been through EMG studies.^[1]

Along with the soleus muscle it forms the calf muscle. Its function is plantar flexing the foot at the ankle joint and flexing the leg at the knee joint.

Clinical significance

The gastrocnemius muscle is prone to spasms, which are painful, involuntary, contractions of the muscle that may last several minutes.^[2]

A severe ankle dorsiflexion force may result in an injury of the muscle, commonly referred to as a "torn" or "strained" calf muscle, which is acutely painful and disabling.

The gastrocnemius muscle may also become inflamed due to overuse. Anti-inflammatory medications and physical therapy (heat, massage, and stretching) may be useful.

Anatomical abnormalities involving the medial head of gastrocnemius muscle result in popliteal artery entrapment syndrome.

History

In a 1967 EMG study, Herman and Bragin concluded that its most important role was plantar flexing in large contractions and in rapid development of tension.^[3]

Additional images

Nerves, arteries and veins surround the gastrocnemius and soleus.
Muscle layer under the gastrocnemius
Cross section of the lower leg
Right femur. Posterior surface.
Back of left lower extremity.
Gastrocnemius muscle
Gastrocnemius muscle
Lateral aspect of right leg.

References

^ Clinically Oriented Anatomy. pp. 598–600. ISBN 978-1-60547-652-0.
^ "Nighttime Leg Cramps". WebMD. August 19, 2010. Retrieved March 7, 2012.
^ Hamilton, Nancy; Luttgens, Kathryn (2001). Kinesiology: Scientific Basis of Human Motion (10th ed.). McGraw-Hill. ISBN 978-0-07-248910-1.

External links

Wikimedia Commons has media related to Gastrocnemius muscle.

-275120049 at GPnotebook
Origin, insertion and nerve supply of the muscle at Loyola University Chicago Stritch School of Medicine
Anatomy photo:14:st-0405 at the SUNY Downstate Medical Center

UpToDate Contents

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1. アキレス腱に至らない脹脛部の傷害 calf injuries not involving the achilles tendon
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3. 膝内側側副靱帯損傷 medial collateral ligament injury of the knee
4. Congenital muscular torticollis: Management and prognosis
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English Journal

Angiotensin-(1-7) decreases skeletal muscle atrophy induced by angiotensin II through a Mas receptor-dependent mechanism.

Cisternas F1, Morales MG1, Meneses C1, Simon F, Brandan E2, Abrigo J1, Vazquez Y1, Cabello-Verrugio C1.
Clinical science (London, England : 1979).Clin Sci (Lond).2015 Mar 1;128(5):307-19. doi: 10.1042/CS20140215.
Skeletal muscle atrophy is a pathological condition characterized by the loss of strength and muscle mass, an increase in myosin heavy chain (MHC) degradation and increase in the expression of two muscle-specific ubiquitin ligases: atrogin-1 and MuRF-1. Angiotensin II (AngII) induces muscle atrophy.
PMID 25222828

Skeletal muscle work efficiency with age: the role of non-contractile processes.

Layec G, Hart CR, Trinity JD, Le Fur Y1, Jeong EK2, Richardson RS.
Clinical science (London, England : 1979).Clin Sci (Lond).2015 Feb 1;128(3):213-23. doi: 10.1042/CS20140274.
Although skeletal muscle work efficiency probably plays a key role in limiting mobility of the elderly, the physiological mechanisms responsible for this diminished function remain incompletely understood. Thus, in the quadriceps of young (n=9) and old (n=10) subjects, we measured the cost of muscle
PMID 25134525

Global MEF2 target gene analysis in cardiac and skeletal muscle reveals novel regulation of DUSP6 by p38MAPK-MEF2 signaling.

Wales S1, Hashemi S1, Blais A2, McDermott JC3.
Nucleic acids research.Nucleic Acids Res.2015 Feb 1;42(18):11349-62. doi: 10.1093/nar/gku813. Epub 2014 Sep 12.
MEF2 plays a profound role in the regulation of transcription in cardiac and skeletal muscle lineages. To define the overlapping and unique MEF2A genomic targets, we utilized ChIP-exo analysis of cardiomyocytes and skeletal myoblasts. Of the 2783 and 1648 MEF2A binding peaks in skeletal myoblasts an
PMID 25217591

Japanese Journal

ラット内側腓腹筋における異なる部位の形態的・組織化学的適応変化 ―ギプス固定による骨格筋萎縮初期での検討―

鈴木英樹,辻本尚弥
愛知教育大学研究報告. 芸術・保健体育・家政・技術科学・創作編 61, 37-39, 2012-03-01
… Rat medial gastrocnemius (MG) muscle is a compartmentalized muscle: two extramuscular nerve branches innervate proximal or distal compartments. … The purpose of this study was to investigate adaptive responses of different compartments on the rat MG muscle in the early phase of skeletal muscle atrophy caused by one-week cast-immobilization. …
NAID 120003934656

The effects of dynamic stretching on plantar flexor muscle-tendon tissue properties

Samukawa Mina,Hattori Masaki,Sugama Naoko,Takeda Naoki
Manual Therapy 16(6), 618-622, 2011-12
NAID 120003660593

Related Pictures

★リンクテーブル★

リンク元	「腓腹筋」「anterior tibial muscle」「soleus muscle」「plantaris muscle」「voluntary muscle」
関連記事	「muscle」

「腓腹筋」

Gastrocnemius muscle
Gray's	p.482
Origin	superior to articular surfaces of lateral condyle of femur and medial condyle of femur
Insertion	tendo calcaneus (achilles tendon) into mid-posterior calcaneus
Artery	sural arteries
Nerve	tibial nerve from the sciatic, specifically, nerve roots S1–S2
Actions	plantar flexes foot, flexes knee
Antagonist	Tibialis anterior muscle
TA	A04.7.02.044
FMA	FMA:22541
	Anatomical terms of muscle