Calf Muscle

What is the calf muscle?

Your calf muscle is in the back of your lower leg, behind your shin bone (tibia). It actually consists of three different muscles: your gastrocnemius, soleus and plantaris. Together, these lower leg muscles help you walk, run, jump, stand on your toes and flex your foot (push your toes down toward the ground).

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.

Where is the calf muscle located?

Your calf muscle is in the posterior — meaning the back part — of your lower leg.

What are the parts of the calf muscle?

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

Gastrocnemius

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

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

Soleus

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

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

Plantaris

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

What does the calf muscle look like?

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

Why would my calf muscle hurt?

Many conditions and disorders can affect your calf muscle. These include:

• Muscle strain: The most common calf injury is a strain. It happens when your 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, like soccer, basketball, football and volleyball.
• Leg cramps: Muscle cramps and muscle spasms in your 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 your gastrocnemius muscle. Providers call it tennis leg because it commonly happens when your leg extends and your foot flexes. Tennis players put their legs in this position when they serve a tennis ball and “push off” suddenly into motion. But it can happen in any sport.
• 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 (like 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 the age of 50 have had leg cramps at some point.

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

Problems in your calf muscles 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 your lower leg.
• Tenderness or bruising in your calf.

How can I keep my calf muscle healthy?

To avoid problems with your calf muscle, you should:

• Maintain a weight that’s healthy for you: 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, like a strain. If you have overweight (a body mass index, or BMI, over 25) or obesity (a BMI over 30), talk to your provider about the weight that’s healthy for you.
• Stay hydrated: Drinking plenty of water and other fluids decreases your chance of getting a leg cramp and prevents dehydration.
• 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 doesn’t cause this side effect.

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 be signs of a serious medical condition, like a blood clot, deep vein thrombosis (DVT), nerve damage or Achilles tendonitis.

Get help right away if you have:

• Edema (swelling), warmth, discoloration (red, purple, brown or black) or tenderness in your calf.
• Numbness or tingling.
• Severe muscle weakness or trouble moving your lower leg.