Gastrocnemius muscle

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Gastrocnemius muscle
Gastrocnemius.png
Human calf muscles
origin
Caput laterale : femur ( epicondylus lateralis )
Caput mediale : femur ( epicondylus medialis )
approach
Calcaneus over the Achilles tendon (Tendo calcaneus)
function
in the upper ankle joint: plantar flexion
in the lower ankle joint: elevation of the inner edge of the foot (supination)
in the knee joint flexion
Innervation
Tibial nerve (branch of the sciatic nerve )
Spinal segments
S1-S2 (L5)

The gastrocnemius muscle , also known as the "double-bellied calf muscle" or twin calf muscle , is a skeletal muscle of the lower extremity , more precisely of the lower leg . He works closely with the soleus ( soleus ) together, they are in the effects on the ankle synergists well and are called triceps surae summarized. The gastrocnemius muscle, a superficial muscle located directly under the skin, determines the relief of the calf. The soleus muscle below it, however, contributes significantly to the arching of the calf when it is tensed.

etymology

The term gastrocnemius is the Latinized form of ancient Greek γαστρο-κνήμη gastro-kneme , the contraction from ancient Greek. γαστἠρ gaster , German , stomach, belly, abdomen ' , and ancient Greek. κνἠμη kneme , German for leg, lower leg, shin and calf ' . Ancient Greek γαστροκνἠμιον gastroknemion means 'the belly of the lower leg' or the 'belly of the shin', but also 'the calf muscle' or 'the calf' for short because of “the bulbous shape of the flesh protruding from the shin”.

Origin and Approach

The muscle has two muscle heads , caput mediale (inner [muscle] head) and caput laterale (lateral [muscle] head), which arise on both sides on the lower part of the thigh bone. In the predators , a small sesamoid ( Os sesamoideum musculi gastrocnemii ) is embedded in each of the two tendons of origin of the muscle . It is also known as a fabella or vesal sesame bone . The fabella also occurs in the lateral head in 10 to 20% of cases in humans, rarely in both heads. Among the two original tendon is in humans each have a bursa , the bursa subtendinea musculi gastrocnemius medial and lateral .

The lower insertion of the muscle is the heel bone (calcaneus). The common tendon ( Achilles tendon ) of the gastrocnemius and soleus muscles runs to this rear protrusion of the foot, which forms a lever and can thus potentially transfer a lot of force to the ankle . The actual force exerted on the ankle depends on the length of the lever, that is, the distance between the ankle axis and the attachment of the tendon.

In slaughtered animals, the muscle is part of the lower shell .

function

As a muscle acting on two joints, it has numerous functions:

  • Flexion of the foot (ie bending the foot downwards): Here it works synergistically with the other foot flexor, the soleus muscle ( clod muscle ). Together they are also known as the triceps surae muscle . For anatomical and systematic reasons, what every person would call stretching based on their perception is called flexion ( plantar flexion ). In animals, this is known as stretching the ankle .
  • Flexion of the knee joint : If the ankle joint is fixed by external forces or antagonists of the gastrocnemius muscle, the muscle can help pull the heel towards the buttocks.
  • Another task is the supination of the foot .
  • In the literature, a significant contribution to the internal rotation of the lower leg by the internal head of the gastrocnemius muscle is occasionally indicated.

With its main function, the angling of the foot downwards, the muscle has an outstanding function when walking , running and jumping, but also in technically supported forms of locomotion such as cycling and rowing. This function plays an extremely important role, especially in sport, when propulsion, like running and cycling, is to be generated without the entire sole of the foot transferring the force to the floor or the pedals, but only the ball of the foot.

Innervation

The gastrocnemius muscle is innervated by the tibial nerve , a branch of the sciatic nerve.

clinic

Failure of the gastrocnemius muscle is a typical sign of Dancing Doberman Disease , a rare neurological disease in pinschers .

See also

Individual evidence

  1. ^ Günter Thiele (editor): Handlexikon der Medizin , Volume 3 (L – R), Urban & Schwarzenberg , Munich, Vienna, Baltimore without year, page 1642.
  2. ↑ Walther Graumann: Compact textbook anatomy . Volume 2, Schattauer, 2004, ISBN 9783794520626 , p. 217.
  3. ↑ limited preview in the Google book search> Ludwig August Kraus: Kritisch-etymologisches medicinisches Lexikon , 2nd edition, Verlag Anton von Haykul Buchdrucker, Vienna 1831, page 337.
  4. Jump up ↑ limited preview in the Google book search> Adolf Faller : The specialist words of anatomy, histology and embryology , 29th edition, JF Bergmann Verlag, Munich 1978, ISBN 978-3-8070-0300-9 , page 87.
  5. ↑ limited preview in the Google book search> Johann Georg Wilhelm Pape : "Hand Wortbuch der Greek Sprache", Friedrich Vieweg Verlag, Volume 1 (A – K), Braunschweig 1842, page 398.
  6. ↑ a b c Franz-Viktor Salomon: muscle tissue. In: Anatomy for veterinary medicine. 2nd ext. Edition. Enke, Stuttgart 2008, ISBN 978-3-8304-1075-1 , p. 231.
  7. ↑ a b Norbert Ulfig: musculoskeletal system: textbook on the general and special anatomy of the musculoskeletal system and systematics of the pathways. Karger Medical and Scientific Publishers, 2002, ISBN 3-8055-7315-4 , p. 129.
  8. ↑ Wolfgang Dauber: Feneis' picture lexicon of anatomy . Georg Thieme, Stuttgart 2005, ISBN 978-3-13-330109-1 , p. 132.
  9. ^ Andre Jaggy: Atlas and textbook of small animal neurology. Schlütersche, 2005, ISBN 3-87706-739-5 , p. 263.