Intercostal Muscles

What are the intercostal muscles?

Your intercostal muscles connect each rib of your ribcage to its neighbors. These muscles are part of your thoracic wall, and the way these muscles flex is part of how you breathe. These muscles span the intercostal spaces — or the gaps between your rib bones. Those gaps also house the nerves and blood vessels that the intercostal muscles rely on.

What do the intercoastal muscles do?

Your intercostal muscles work together to expand and shrink the space inside your ribcage. You have three types of intercostal muscles:

• External intercostal muscles. These mainly contribute to inhaling.
• Internal intercostal muscles. These mainly contribute to exhaling.
• Innermost intercostal muscles. These support the internal intercostal muscles when you exhale.

The internal and external intercostal muscles work like rowing teams pulling in sync. When you inhale, the external intercostal muscles pull together to expand your rib cage. When your rib cage expands, the increased volume (space) inside your lungs creates suction, pulling air in. When you exhale, the internal intercostal muscles work similarly. When your rib cage shrinks, that pushes air out of your lungs and makes you exhale.

Some types of breathing rely mainly on your intercostal muscles. Your intercostal muscles also work cooperatively with other muscles. An example is how they work with your diaphragm when you take deeper breaths.

The intercostal muscles also contribute to other things that involve taking a breath. That includes things like forcefully pushing air out of your lungs when you sigh or cough.

Where are the intercostal muscles located?

The intercostal muscles get their name from Latin words that mean “between ribs.” They span the 11 intercostal spaces, the gaps between your 12 ribs. Each of your ribs is like a curved beam that wraps around your thorax (your chest and the areas of your sides and back behind it).

Most intercostal muscles attach to two ribs, one above and one below. And each type of intercostal muscle has a specific location between those ribs.

• External intercostal muscles (11 pairs). These are the frontmost of the intercostal muscles.
• Internal intercostal muscles (11 pairs). These are right behind the external intercostal muscles but you only have them at the front of your body.
• Innermost intercostal muscles. This muscle layer attaches to the rear surface of both ribs and may skip ribs.

What are the common conditions and disorders that affect the intercostal muscles?

Several conditions and injuries can affect the intercostal muscles directly or indirectly. Some examples include:

• Muscle injuries like strains, tears, spasms (cramps) and hernias
• Bone injuries like fractured ribs
• Conditions that disrupt signals from your brain, like amyotrophic lateral sclerosis (ALS)
• Paralysis from spinal cord injuries or nerve damage
• Medical procedures like thoracostomy

Sometimes, your provider may suspect other causes of musculoskeletal chest pain, like costochondritis. Costochondritis doesn’t affect the intercostal muscles directly, but it can cause similar symptoms. Instead, it affects the costochondral joints, which are next to the intercostal muscles.

What are some common signs or symptoms of intercostal muscle conditions?

Symptoms that might affect your intercostal muscles include:

• Musculoskeletal chest pain
• Swelling
• Bruising
• Weakness or paralysis
• Intercostal retractions (which need emergency care)

What are some common tests to check the intercostal muscles?

Healthcare providers can check your intercostal muscles during a physical exam. They can also use imaging tests like ultrasound or magnetic resonance imaging (MRI). To check the nerve connections, they can use a nerve conduction study and/or electromyography.

Other tests might be possible, depending on the specifics of your case. Your healthcare provider is the best person to tell you about tests that might help you.

What are some common treatments for the intercostal muscles?

The treatments for intercostal muscle conditions vary widely. Factors that may play a role include your underlying condition, how it’s affecting your muscles and more.

Many conditions or issues that affect your intercostal muscles don’t need treatment and will get better on their own. Other conditions — like minor intercostal strains — are things you can manage on your own.

But conditions that affect your intercostal muscles are more serious and need expert guidance. Your healthcare provider is the best person to tell you more about whether you need treatment and what your options are.