Calf Muscle

Overview

What is the calf muscle?

The calf muscle is in the back of your lower leg, behind your shin bone. It actually includes three muscles. Together, the muscles help you walk, run, jump, stand on your toes and flex your foot (lift your toes up toward your knee).

Function

What is the purpose of the calf muscle?

Your calf muscle supports you when you stand and enables you to move your foot and your lower leg. It propels (pushes) you forward when you walk or run. It also allows you to jump, rotate your ankle, flex your foot and “lock” your knee.

Anatomy

Where is the calf muscle?

Your calf muscle consists of two main muscles — the gastrocnemius and the soleus. Because these two muscles come together above your heel and attach to the Achilles tendon, some providers refer to the gastrocnemius and soleus as one large muscle with two sections.

In addition to these two large muscles, a small muscle called the plantaris runs between the gastrocnemius and soleus down the length of the lower leg. Providers call these three muscles the triceps surae. But not everyone has a plantaris muscle. About 10% of people only have two larger muscles.

The main muscles in the calf are:

Gastrocnemius: This muscle is just under your skin at the back of the lower leg. Because the gastrocnemius is close to the skin’s surface, you can often see its outline. It forms the bulk of your calf muscle.

The top part of the gastrocnemius has two heads that start on the inside and the outside of the femur (thighbone). The gastrocnemius goes down the back of the leg and attaches to the Achilles tendon. Gastrocnemius strains are common because the muscle connects to two joints (the knee joint and the ankle joint).

Soleus: The soleus is a wide, flat muscle that sits slightly deeper than the gastrocnemius. It starts just below your knee, runs down your lower leg and connects to the Achilles tendon above the heel. Soleus injuries are less common because the muscle only crosses the ankle joint.

The soleus connects to your tibia and fibula (the bones in your lower leg). Together with your gastrocnemius, the soleus helps you walk, run and jump. It also helps your legs support you so you can maintain good posture.

What does the calf muscle look like?

As part of your musculoskeletal system, the gastrocnemius and soleus are a type of muscle called skeletal muscle. Many individual fibers make up skeletal muscles. These fibers bundle together to create a striated, or striped, appearance.

Conditions and Disorders

What conditions and disorders affect the calf muscle?

Conditions that affect the calf muscle include:

  • Muscle strain: The most common calf injury is a strain. It happens when the muscle fibers stretch too far or tear. It usually results from strenuous exercise or overuse. This injury is common in activities like running and sports that require jumping or quick stops and starts, such as soccer, basketball, football and volleyball.
  • Leg cramps: Muscle cramps and muscle spasms in the calves can be very painful. Leg cramps can happen during the day or at night. They can result from several factors, including pregnancy, dehydration, some medications and certain health conditions.
  • Tennis leg: This type of muscle strain injury affects the gastrocnemius muscle. Providers call it tennis leg because it commonly happens when the leg extends and the foot flexes. But it can happen in any sport. Tennis players put their leg in this position when they serve a tennis ball and “push off” suddenly into motion.
  • Compartment syndrome: A serious, life-threatening condition, compartment syndrome happens when pressure builds up inside a muscle. The pressure decreases the flow of blood and oxygen. The injury can result from trauma (such as a fracture) or strenuous exercise.

How common are these conditions?

Calf muscle strain is one of the most common muscle strain injuries among athletes. People who play sports that require sprinting and quick footwork have an increased risk of this type of injury.

Leg cramps are also very common, and they’re more likely to happen as you age. Providers estimate that about 75% of people over age 50 have had leg cramps at some point.

What are some common signs or symptoms of conditions affecting the calf muscle?

Problems in the calf muscle can cause:

  • Calf muscle pain, tightness and stiffness. The pain may be sharp or dull. It may start out as mild pain and slowly worsen.
  • Limited mobility (ability to move), decreased range of motion or muscle weakness.
  • A noticeable bulge or lump in the back of the lower leg.
  • Tenderness or bruising in the calf.

Care

How can I keep my calf muscle healthy?

To avoid problems with your calf muscles, you should:

  • Maintain a healthy weight: People who carry extra weight are more likely to pull a muscle. Excess pounds put pressure on your legs and put you at a higher risk of an injury, such as a strain. If you’re obese or overweight, talk to your provider about the most appropriate weight for you.
  • Stay hydrated: Drinking plenty of water and other fluids decreases your chance of getting a leg cramp.
  • Stretch and warm up before exercising: Calf muscles that are warm are less likely to stretch too far or tear. Before doing physical activity, be sure to do a warm-up program to stretch your calves and increase flexibility. When exercising, increase the intensity gradually.
  • Watch your medications: Certain medications can cause leg cramps. Talk to your provider about taking another drug that does not cause this side effect.

Frequently Asked Questions

When should I call my doctor about my calf muscle?

If you have severe or sudden calf pain that doesn’t improve after a day or two of rest, call your provider. Calf pain and other symptoms of a muscle strain may actually be signs of a serious medical condition, such as a blood clot, deep vein thrombosis (DVT), nerve damage or Achilles tendonitis.

Get help right away if you have:

  • Edema (swelling), warmth, redness or tenderness in the calf.
  • Numbness or tingling.
  • Severe muscle weakness or trouble moving your lower leg.

A note from Cleveland Clinic

Your calf muscle helps you move your lower legs, feet and ankles. It allows you to flex your feet, walk, run and leap. It also supports and stabilizes your legs and enables you to stand up straight. Calf pain from muscle strains and leg cramps is very common. You can keep your calf muscles strong by staying active, drinking plenty of water and warming up before you exercise. Call your provider if you have calf tenderness that doesn’t get better in a day or two — or if you have swelling, redness or severe pain.

Last reviewed by a Cleveland Clinic medical professional on 08/05/2021.

References

  • Binstead JT, Munjal A, Varacallo M. Anatomy, Bony Pelvis and Lower Limb, Calf. [Updated 2020 Aug 22]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan-. https://www.ncbi.nlm.nih.gov/books/NBK459362/ (https://www.ncbi.nlm.nih.gov/books/NBK459362/) . Accessed 6/4/2021.
  • Bright JM, Fields KB, Draper R. Ultrasound Diagnosis of Calf Injuries. Sports Health. 2017 Jul-Aug;9(4):352-355. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5496702/ (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5496702/) . Accessed 6/4/2021.
  • Young G. Leg cramps. BMJ Clinical Evididence. 2015 May 13;2015:1113. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4429847/ (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4429847/) . Accessed 6/4/2021.

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