Why are Ribs 8-10 Called False Ribs?

Ribs 8, 9, and 10 are classified as "false ribs" because they do not directly connect to the sternum, unlike the true ribs.

Understanding False Ribs

The rib cage protects vital organs and is made up of 12 pairs of ribs. These ribs are categorized based on how they attach to the sternum (breastbone):

• True Ribs (1-7): These ribs connect directly to the sternum through their own costal cartilages.
• False Ribs (8-10): As highlighted by the reference, their costal cartilages do not articulate directly with the sternum. Instead, their cartilage connects to the cartilage of the rib above them. This shared connection ultimately links to the sternum, but not via a direct, individual cartilage connection.
• Floating Ribs (11-12): These ribs are also considered "false" and do not connect to the sternum at all.

Costal Cartilage Connection

The key distinction is in the way the costal cartilage interacts with the sternum. For ribs 8 to 10:

• The costal cartilage of rib 8 connects to the costal cartilage of rib 7.
• The costal cartilage of rib 9 connects to the costal cartilage of rib 8.
• The costal cartilage of rib 10 connects to the costal cartilage of rib 9.

This chain-like connection is why they are referred to as false ribs. The true ribs have a direct connection, but the false ribs do not.

Summary Table

Therefore, the reason why ribs 8 to 10 are false is due to their costal cartilages not directly attaching to the sternum but instead connecting to the cartilage of the rib above.