Floating ribs are called "floating ribs" because they are not attached to the sternum (breastbone) or to any other costal cartilage on their anterior (front) end.
Here's a more detailed explanation:
- Rib Cage Structure: The human rib cage consists of 12 pairs of ribs.
- True Ribs (1-7): The first seven pairs, called true ribs, are directly connected to the sternum via their own costal cartilage.
- False Ribs (8-10): Ribs 8 through 10 are called false ribs. They connect to the sternum indirectly, via the costal cartilage of the rib above them.
- Floating Ribs (11-12): The last two pairs, ribs 11 and 12, are the floating ribs. These ribs only attach to the vertebrae in the back. The front end of the rib is free and "floats" in the torso. They do not have anterior attachments to either the sternum or the costal cartilage of other ribs. This lack of anterior connection gives them the name "floating ribs".
In essence, the term "floating" describes the fact that these ribs don't connect to the sternum or other ribs in the front of the chest. This unique characteristic distinguishes them from the true and false ribs, providing flexibility and movement in the lower rib cage.
