Gastrocnemius muscle
From Wikipedia, the free encyclopedia
| 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 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.
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[edit] Anatomy
The gastrocnemius is located with the soleus in the posterior (back) compartment of the leg. It originates from the posterior (back) surfaces of the distal head 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.
[edit] Clinical significance
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
[edit] Additional images
 Right femur. Posterior surface. |
 Cross-section through middle of leg. |
 Back of left lower extremity. |
[edit] External links
- WebMD Nighttime Leg Cramps: http://www.webmd.com/a-to-z-guides/nighttime-leg-cramps-topic-overview
- -275120049 at GPnotebook
- LUC gast
- SUNY Labs 14:st-0405
- Anatomy at Dartmouth knee/surface/surface4
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