Introduction

The thoracic cavity is a space inside your chest that protects and holds some of the most important organs in your body. The thoracic cavity is like a big box in your upper body, between your neck and your diaphragm (a strong muscle that helps you breathe). This “box” is surrounded by your ribs, your spine (at the back), and your sternum (breastbone in front).

What’s inside the thoracic cavity?

It holds three main things:

1. Lungs – You have two lungs, one on each side. They help you breathe.

2. Heart – In the middle, slightly to the left. It pumps blood to your whole body.

3. Other important parts:

   • Esophagus – The food pipe that carries food from your mouth to your stomach.

   • Trachea – The windpipe that brings air to your lungs.

   • Blood vessels – Like the aorta and vena cava (big tubes carrying blood).

   • Thymus gland – Important for your immune system (especially in children).

The thoracic cavity is divided into parts:

• Left and right pleural cavities – They each hold a lung.

• Mediastinum – The middle part that holds the heart, esophagus, trachea, and big blood vessels.

• Pericardial cavity – A smaller space inside the mediastinum that surrounds the heart.

Why is it important?

• It protects your heart and lungs using the rib cage.

• It helps with breathing. When you breathe in, the diaphragm and muscles around it move to pull air into your lungs.

• It keeps the organs in place, and they’re separated by thin membranes so they don’t rub against each other.