Rib Cage - Side View
The last two pairs of bones are called floating ribs. Floating ribs are smaller than the true ribs and the false ribs. They are attached to the spine at the back, but are not connected to anything in the front. The front floats free, hence their name floating ribs.
It is much easier to see the floating ribs in the rib cage side view diagram to the right. The bottom two ribs (11 and 12) are clearly not attached to the front sternum. They are also not attached to other ribs as with the false ribs.
The twelve pairs of ribs are often called the "rib cage." This is because they form a kind of cage that encloses the upper body. This cage gives the chest its familiar barrel-like shape.
Rib Cage - Posterior or Back View
The last diagram shows how the ribs are connected to the vertebral column or spine. This securely holds the ribs in place at the back.
The ribs serve several important purposes. They protect the heart and lungs from injuries and shocks that might damage them. Ribs also protect parts of the stomach, spleen, and kidneys. The ribs help you to breathe. As you inhale, the muscles in between the ribs lift the rib cage up, allowing the lungs to expand. When you exhale, the rib cage moves down again, squeezing the air out of your lungs.