| Gastrocnemius muscle | |
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| Lateral aspect of right leg. | |
| Gray's | subject #129 482 |
| Origin | superior to articular surfaces of lateral condyle of femur and medial condyle of femur |
| Insertion | tendo calcaneus (achilles tendon) into mid-posteior 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 |
In humans, the gastrocnemius (pronounced /ˌɡæstrɒkˈniːmiəs/ or /ˌɡæstrəˈniːmiəs/) muscle, meaning 'calf of the leg' (modern Latin, from Greek gastr- ‘a calf muscle that pushes downward’ and knēmē ‘leg’, referring to the the bulging shape of the calf), is a very powerful superficial muscle that is in the back part of the lower leg and also called the calf. It runs from its two heads just above the knee to the heel, and is involved in standing, walking, running and jumping. 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. 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.
Contents |
The gastrocnemius is located with the soleus in the posterior (back) compartment of the leg. Lateral Head originates from 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 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. The plantaris 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 and the tibial nerve. 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 midshaft of the tibia. Frequently there is a sesamoid bone called the "fabella" in the lateral head of gastrocnemius muscle.
The gastrocnemius muscle is very prone to spasms; the painful, involuntary, contraction of the muscle for up to several minutes.[1]
This muscle is prone to injury called torn calf muscle which is disabling.
The Gastrocnemius muscle may also become inflamed due to overuse. Anti-inflammatory and physical therapy may be necessary.
Anatomical abnormalities involving the medial head of gastrocnemius muscle results in popliteal entrapment syndrome
 Right femur. Posterior surface. |
 Cross-section through middle of leg. |
 Back of left lower extremity. |
Kinesiology: Scientific Basis of Human Motion
Nancy Hamilton, Ph.D. Associate Professor, University of Northern Iowa
Kathryn Luttgens, Ph.D. Professor Emerita, Northeastern University
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