F. The Thoracic Cage

Learning Objectives

Understand the structure and function of the thoracic cage, including the sternum, ribs, costal cartilages, and thoracic vertebrae.
Identify the parts of the thoracic cage
Distinguish between true, false, and floating ribs
Understand how ribs articulate with the thoracic vertebrae

Introduction

The thoracic cage is a protective and supportive structure that forms the chest wall. It includes the sternum, thoracic vertebrae, ribs, and costal cartilages (made of hyaline cartilage). Together, these elements:

Shield vital organs such as the heart and lungs and other structures in the thoracic cavity
Provide attachment points for muscles involved in
- breathing
- upper limb movement
- moving the pectoral (shoulder) girdles (clavicles/scapulae)
- supporting the position of the vertebral column

You’ll learn this anatomy through:

Lab skeletons and disarticulated bones
3D interactive models
Labeling and review activities

✅ Nice work! Now let’s dive into the anatomy visually.

Start by watching these animations to gain a broad overview of the thoracic cage’s structure.

AnatomyTOOL: The Sternum Learn the three parts of the sternum and their anatomical relationships.

2. AnatomyTOOL: Rib Cage Overview
Explore how the ribs connect to the sternum and thoracic vertebrae.

3. AnatomyZone: The Thoracic Cage (5:23)
Review rib classification, rib-sternum articulation, and intercostal spaces.

4. Practice in 3D: Thoracic Cage Model on Sketchfab
Now that you’ve reviewed the thoracic cage in motion, explore this interactive 3D model to identify key bones and articulations. Rotate, zoom, and test your understanding in real time.
👉Explore on Sketchfab.

👉Click here to use this interactive InnerBody tool to dive into the bones of the thoracic cage.

📌 What to do:

Click each bone to view its name
Use the Anatomy Explorer menu for descriptions
Rotate and zoom to view the thoracic cage from different angles
Focus on ribs, sternum, and thoracic vertebrae

Perfect for building spatial understanding before lab work!

For those who want to go deeper into individual vertebra anatomy:

👉BlueLink 3D: First Thoracic Vertebra (T1)

👉BlueLink 3D: Eighth Thoracic Vertebra (T8)

These models allow close inspection of vertebral features like spinous processes, costal facets, and vertebral foramen.

Components to Identify:

Sternum
- Manubrium (uppermost bone that articulates with clavicle & 1st rib)
- Mesosternum (middle bone known as the body)
- Xiphoid process (lowest bone)

🧩 Try this:

🦴Rib Classification

The human rib cage is typically composed of 12 pairs of ribs, though some people may have 11 or 13.

Type of Rib	Rib Numbers	Attachment
True Ribs	1–7	Directly attached to the sternum via individual costal cartilage
False Ribs	8–12	Do not attach directly to the sternum
➤ Typical False Ribs	8–10	Attach to the sternum indirectly via cartilage of rib 7
➤ Floating Ribs	11–12	No anterior attachment to the sternum at all — they end in the posterior abdominal wall

Additional Thoracic Cage Features

Intercostal Spaces: The gaps between ribs, filled with intercostal muscles that assist in breathing.
Costal Cartilage: Flexible hyaline cartilage that connects the anterior ends of the ribs to the sternum, allowing for chest expansion during respiration.

🧩 Try this:

✅ Test Your Knowledge

Identify the Fourth Right Rib
Test your knowledge of rib features by identifying two parts of the fourth right rib.
👉 Launch activity

Beat the Clock: Rib Articulation Game
How fast can you match rib numbers to their vertebral and sternal articulations?
👉 Start the game

Beat the Clock: Identify Parts of the Rib Cage
Challenge yourself to locate and name thoracic cage components under time pressure.
👉 Play now