Gastrocnemius muscle - wikipedia Gastrocnemius muscle Gastrocnemius muscle Details 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 Identifiers TA A04. 7.02. 044 FMA 22541 Anatomical terms of muscle ( edit on Wikidata ) In humans, the gastrocnemius muscle ( / ˌɡæstrɒkˈniːmiəs / or / ˌɡæstrəkˈniːmiəs / ; plural gastrocnemii ; Latin, from Greek γαστήρ `` stomach '' and κνήμη ( knḗmē ) `` 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, a two joint muscle. Contents 1 Structure 1.1 Variation 2 Function 3 Motor pathway 4 Clinical significance 5 History 6 Additional images 7 References 8 External links 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 `` three - headed ( muscle ) of the calf '', 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 ( outer ) head of gastrocnemius muscle. Function Along with the soleus muscle, the gastrocnemius forms half of the calf muscle. Its function is plantar flexing the foot at the ankle joint and flexing the leg at the knee joint. The gastrocnemius is primarily involved in running, jumping and other `` fast '' movements of leg, and to a lesser degree in walking and standing. This specialization is connected to the predominance of white muscle fibers ( type II fast twitch ) present in the gastrocnemius, as opposed to the soleus, which has more red muscle fibers ( type I slow twitch ) and is the primary active muscle when standing still, as determined by EMG studies. Motor pathway The plan to use the gastrocnemius in running, jumping, knee and plantar flexing is created in the precentral gyrus in the cerebrum of the brain. Once a plan is produced, the signal is sent to and down an upper motor neuron. The signal is passed through the internal capsule and decussates, or crosses, in the medulla oblongata, specifically in the lateral corticospinal tract. The signal continues down through the anterior horn of the spinal cord where the upper motor neuron synapses with the lower motor neuron. Signal propagation continues down the anterior rami ( Lumbar 4 - 5 and Sacral 1 - 5 ) of the sacral plexus. The sciatic nerve branches off of the sacral plexus in which the tibial and common fibular nerves are wrapped in one sheath. The tibial nerve eventually separates from the sciatic nerve and innervates the gastrocnemius muscle. Thus, completing the plan the brain had originally started with, so that the actions of running, standing, and jumping could be executed. Clinical significance The gastrocnemius muscle is prone to spasms, which are painful, involuntary contractions of the muscle that may last several minutes. 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. Ultrasound of medial gastrocnemius strain 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. Additional images Nerves, arteries and veins surrounding 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 Jump up ^ Clinically Oriented Anatomy. pp. 598 -- 600. ISBN 978 - 1 - 60547 - 652 - 0. ^ Jump up to : Hamilton, Nancy ; Luttgens, Kathryn ( 2001 ). Kinesiology : Scientific Basis of Human Motion ( 10th ed. ). McGraw - Hill. ISBN 978 - 0 - 07 - 248910 - 1. Jump up ^ Freberg, Laura ( 2015 - 01 - 01 ). Discovering Behavioral Neuroscience : An Introduction to Biological Psychology. Cengage Learning. ISBN 9781305687738. Jump up ^ Saladin, Kenneth ( 2015 ). Anatomy & Physiology : The Unity of Form and Function. McGraw - Hill Education. Jump up ^ `` Nighttime Leg Cramps ''. WebMD. August 19, 2010. Retrieved March 7, 2012. External links Wikimedia Commons has media related to Gastrocnemius muscle. Anatomy photo : 14 : st - 0405 at the SUNY Downstate Medical Center Muscles of the hip and human leg Iliac region Iliopsoas psoas major / psoas minor iliacus Buttocks Gluteal muscles maximus medius minimus tensor fasciae latae lateral rotator group : quadratus femoris inferior gemellus superior gemellus internal obturator external obturator piriformis Thigh / compartments Anterior sartorius quadriceps rectus femoris vastus lateralis vastus intermedius vastus medialis articularis genus Posterior hamstring biceps femoris semitendinosus semimembranosus Medial pectineus external obturator gracilis adductor longus brevis magnus minimus Fascia Femoral sheath Femoral canal Femoral ring Adductor canal Adductor hiatus Muscular lacuna fascia lata Iliotibial tract Lateral intermuscular septum of thigh Medial intermuscular septum of thigh Cribriform fascia Leg / compartments Anterior tibialis anterior extensor hallucis longus extensor digitorum longus peroneus tertius Posterior superficial triceps surae gastrocnemius soleus accessory soleus Achilles tendon plantaris deep tarsal tunnel flexor hallucis longus flexor digitorum longus tibialis posterior popliteus Lateral peroneus muscles longus brevis Fascia Pes anserinus Intermuscular septa anterior posterior transverse Foot Dorsal extensor hallucis brevis extensor digitorum brevis Plantar 1st layer abductor hallucis flexor digitorum brevis abductor digiti minimi 2nd layer quadratus plantae lumbrical muscle 3rd layer flexor hallucis brevis adductor hallucis flexor digiti minimi brevis 4th layer dorsal interossei plantar interossei Fascia Plantar fascia retinacula Peroneal Inferior extensor Superior extensor Flexor Retrieved from `` https://en.wikipedia.org/w/index.php?title=Gastrocnemius_muscle&oldid=798110435 '' Categories : Calf muscles Knee flexors Plantar flexors Muscles of the lower limb Hidden categories : Medicine infobox template using GraySubject or GrayPage Talk Contents About Wikipedia Azərbaycanca Беларуская Беларуская ( тарашкевіца ) ‎ Català Deutsch Español Esperanto فارسی Français Hrvatski Italiano עברית Latina Lietuvių Nederlands 日本 語 Polski Português Русский Slovenščina Suomi Svenska Українська 中文 Edit links This page was last edited on 31 August 2017, at 01 : 43. 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Question: what is the name of the main muscle that forms the calf
Answer: gastrocnemius muscle