Gastrocnemius muscle
Encyclopedia
In humans, the gastrocnemius muscle (icon or ˌ; Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...

, from Greek
Greek language
Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...

 γαστήρ "stomach" and knēmē "leg"; meaning "stomach of leg", referring to the bulging shape of the calf) is a very powerful superficial pennate muscle
Pennate muscle
A pennate or pinnate muscle is a muscle with fascicles that attach obliquely to its tendon...

 that is in the back part of the lower leg. It runs from its two heads just above the knee
Knee
The knee joint joins the thigh with the leg and consists of two articulations: one between the fibula and tibia, and one between the femur and patella. It is the largest joint in the human body and is very complicated. The knee is a mobile trocho-ginglymus , which permits flexion and extension as...

 to the heel, and is involved in standing, walking, running and jumping. Along with the soleus muscle
Soleus muscle
- References :* Gray, Henry. Pick, T. Pickering, & Howden, Robert . Gray's Anatomy . New York: Barnes & Noble Books.- External links :...

 it forms the calf muscle
Triceps surae muscle
The triceps surae is a pair of muscles located at the calf - the gastrocnemius and the soleus...

. Its function is plantar flexing the foot at the ankle joint and flexing the leg at the knee joint. 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.

The gastrocnemius is located with the soleus
Soleus muscle
- References :* Gray, Henry. Pick, T. Pickering, & Howden, Robert . Gray's Anatomy . New York: Barnes & Noble Books.- External links :...

 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
Femur
The femur , or thigh bone, is the most proximal bone of the leg in tetrapod vertebrates capable of walking or jumping, such as most land mammals, birds, many reptiles such as lizards, and amphibians such as frogs. In vertebrates with four legs such as dogs and horses, the femur is found only in...

. Its other end forms a common tendon with the soleus muscle
Soleus muscle
- References :* Gray, Henry. Pick, T. Pickering, & Howden, Robert . Gray's Anatomy . New York: Barnes & Noble Books.- External links :...

; this tendon is known as the calcaneal tendon or Achilles Tendon
Achilles tendon
The Achilles tendon , also known as the calcaneal tendon or the tendo calcaneus, is a tendon of the posterior leg. It serves to attach the plantaris, gastrocnemius and soleus muscles to the calcaneus bone.- Anatomy :The Achilles is the tendonous extension of 3 muscles in the lower leg:...

 and inserts onto the posterior surface of the calcaneus, or mountain 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
Triceps surae muscle
The triceps surae is a pair of muscles located at the calf - the gastrocnemius and the soleus...

. The plantaris
Plantaris muscle
Plantaris is a vestigial structure and one of the superficial muscles of the posterior crural compartment of the leg.It is innervated by the tibial nerve ....

 muscle and a portion of its tendon run between the two muscles, which is involved in "locking" the knee from the standing and posterior tibial vein
Posterior tibial vein
In anatomy, the posterior tibial vein of the lower limb carries blood from the posterior compartment and plantar surface of the foot to the popliteal vein which it forms when it joins with the anterior tibial vein....

 and the tibial nerve. Since the anterior compartment of the leg is lateral to the tibia, the bulge of muscle medial to the tibia
Tibia
The tibia , shinbone, or shankbone is the larger and stronger of the two bones in the leg below the knee in vertebrates , and connects the knee with the ankle bones....

 on the anterior side is actually the posterior compartment. The soleus is superficial to the mid-shaft of the tibia.
Frequently there is a sesamoid bone
Sesamoid bone
In anatomy, a sesamoid bone is a bone embedded within a tendon.Sesamoids are found in locations where a tendon passes over a joint, such as the hand, knee, and foot. Functionally, they act to protect the tendon and to increase its mechanical effect. The presence of the sesamoid bone holds the...

 called the "fabella
Fabella
The fabella is a small sesamoid bone found in some mammals embedded in the tendon of the lateral head of the gastrocnemius muscle behind the lateral condyle of the femur. It is a variant of normal anatomy and present in humans in 10% to 30% of individuals. Rarely, there are 2 or 3 of these bones...

" in the lateral head of gastrocnemius muscle.

Clinical significance

The gastrocnemius muscle is very prone to spasm
Spasm
In medicine a spasm is a sudden, involuntary contraction of a muscle, a group of muscles, or a hollow organ, or a similarly sudden contraction of an orifice. It is sometimes accompanied by a sudden burst of pain, but is usually harmless and ceases after a few minutes...

s; the painful, involuntary, contraction of the muscle for up to several minutes.http://www.webmd.com/a-to-z-guides/nighttime-leg-cramps-topic-overview

This muscle is prone to injury called torn calf muscle
Triceps surae muscle
The triceps surae is a pair of muscles located at the calf - the gastrocnemius and the soleus...

, which is disabling.

The Gastrocnemius muscle may also become inflamed
Inflammation
Inflammation is part of the complex biological response of vascular tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. Inflammation is a protective attempt by the organism to remove the injurious stimuli and to initiate the healing process...

 due to overuse. Anti-inflammatory
Anti-inflammatory
Anti-inflammatory refers to the property of a substance or treatment that reduces inflammation. Anti-inflammatory drugs make up about half of analgesics, remedying pain by reducing inflammation as opposed to opioids, which affect the central nervous system....

 and physical therapy may be necessary.

Anatomical abnormalities involving the medial head of gastrocnemius muscle results in popliteal artery entrapment syndrome
Popliteal artery entrapment syndrome
The popliteal artery entrapment syndrome is a rather uncommon pathology, which results into claudication and chronic leg ischemia. The popliteal artery may be compressed behind the knee, due to congenital deformity of the muscles or tendon insertions of the popliteal space...

.

External links

  • WebMD Nighttime Leg Cramps: http://www.webmd.com/a-to-z-guides/nighttime-leg-cramps-topic-overview
The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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