Thoracic Cavity

What is it?

Your thoracic cavity (chest cavity) is a space inside your thorax (chest) that contains your heart, lungs and other organs and tissues. It’s the second biggest hollow space in your body, with only your abdominal cavity being larger.

What is the function of the thoracic cavity?

Your thoracic cavity houses the organs and tissues in your chest. These organs and tissues play a vital role in many of your body’s systems, including your:

• Cardiovascular system.
• Digestive system.
• Immune system.
• Nervous system.
• Respiratory system.

What organs are in the thoracic cavity?

Your thoracic cavity contains five organs:

• Esophagus (food tube).
• Heart.
• Lungs.
• Thymus.
• Trachea (windpipe).

Where is the thoracic cavity located?

Your thoracic cavity is located in your chest. It’s enclosed by the bones and muscles that make up your chest wall. Your thoracic cavity begins just below your neck and ends at the bottom of your ribcage.

Here’s a bit more detail about your thoracic cavity’s boundaries at different locations within your chest:

• Top boundary: The top boundary is your superior thoracic aperture (also called your thoracic inlet or thoracic outlet). This is an opening at the base of your neck that connects your neck with your chest. Your esophagus and trachea pass through this opening to enter your thoracic cavity. Many blood vessels, nerves and other structures also pass through it.
• Bottom boundary: The bottom boundary is your diaphragm. This is a dome-shaped muscle that sits just beneath your heart and lungs. Your diaphragm is what separates your thoracic cavity from your abdominal cavity. Several blood vessels, nerves and tissues pass through your diaphragm as they travel between your chest and belly. These include your aorta, esophagus and vagus nerve.
• Front boundary: The front boundary is your sternum (breastbone). This is a long, vertical bone that extends down the middle of your chest.
• Back boundary: Your back boundary is your thoracic spine. This is the middle section of your spine, which extends from the base of your neck to the bottom of your ribcage.
• Boundary around the sides:These are your ribs. You have 12 pairs of ribs that wrap around the sides of your body and protect the structures inside your chest cavity.

Your thoracic cavity contains three main sections. Your mediastinum is in the middle. Your pleural cavities (left and right) are on either side.

What are the parts of the thoracic cavity?

Your thoracic cavity is like a home with many rooms. There are three main “rooms” in your thoracic cavity:

• Right pleural cavity: Located in the right side of your chest.
• Left pleural cavity: Located in the left side of your chest.
• Mediastinum: Located in the middle of your chest, between the two pleural cavities.

Your mediastinum is further divided into several parts. They’re named according to their position in your chest. There are two main classification systems that scientists use. The first is an older system that divides the mediastinum into four parts:

• Superior mediastinum: The top part, located superior to (above) your heart.
• Anterior mediastinum: The part anterior to (in front of) your heart, between your heart and your sternum (breastbone).
• Middle mediastinum: The part that contains your heart.
• Posterior mediastinum: The part posterior to (behind) your heart.

A more recent classification system divides the mediastinum into three parts with different names:

• Prevascular compartment: The part in front of your heart.
• Visceral compartment: The middle part that contains your heart.
• Paravertebral compartment: The part behind your heart.

The older model is based on X-ray images of your heart. The newer model is based on cross-sectional imaging (like CT scans). So, the newer model is helpful for healthcare providers who use cross-sectional imaging for diagnosis and treatment.

What does the thoracic cavity include?

Your thoracic cavity includes organs, blood vessels, nerves and connective tissues. Some key components include:

• Esophageal plexus.
• Esophagus.
• Fat tissue.
• Heart and pericardium.
• Left brachiocephalic vein.
• Lungs and pleura.
• Lymph nodes.
• Paravertebral soft tissues.
• Phrenic nerves.
• Pulmonary trunk.
• Superior vena cava.
• Sympathetic chain.
• Thoracic aorta.
• Thoracic lymphatic duct.
• Thoracic spine.
• Thymus.
• Trachea and main bronchi.
• Vagus nerves.

What lines the thoracic cavity?

A thin membrane called the pleura lines your thoracic cavity. This layer of tissue helps protect the organs and structures inside your thoracic cavity.

What common conditions and disorders affect the thoracic cavity?

A wide range of conditions and disorders can affect the organs and tissues within your thoracic cavity. These include:

• Aortic aneurysm.
• Aortic dissection.
• Cardiac tamponade.
• Collapsed lung (pneumothorax).
• Lung cancer.
• Heart disease and congenital heart disease.
• Mediastinal masses.
• Pericardial effusion.
• Pleurisy.

Common tests to check the health of the thoracic cavity

There are many tests your healthcare provider may use to check the health of organs and tissues in your thoracic cavity, including:

• Bronchoscopy.
• Chest X-ray.
• Computed tomography (CT) scan.
• Mediastinoscopy.
• Thoracoscopy.

What can I do to keep my thoracic cavity healthy?

There’s a lot you can do to keep the organs and tissues in your thoracic cavity healthy. Here are some tips:

• Don’t smoke, vape or use any tobacco products.
• Exercise regularly. Aim for 150 minutes of moderate-intensity exercise per week.
• Follow a heart-healthy diet. This includes limiting saturated fat, sodium and sugar.
• Visit a healthcare provider for yearly checkups.

A note from Cleveland Clinic

Your thoracic cavity is the large space in your chest where some of your body’s most important work gets done. If you’re interested in learning about the thoracic cavity, you may have had a recent lung or heart disease diagnosis. Or maybe you just want to know more about the human body. Either way, your healthcare provider can help you learn more. Ask them to share resources or help explain anything that you find confusing as you learn about the inner workings of your body.