The Skeletal System
The ribcage is made up of 12 pairs of curved ribs (24 ribs). They are all attached in the back to the thoracic vertebrae. The top 7 pairs are called true ribs and are attached right to the sternum (or breastbone) in the front.
The bottom 5 pairs are called false ribs. The top 3 false ribs are connected to the sternum in front only by a cartilage bridge. The bottom 2 ribs don’t attach in front at all! They are called floating ribs. Ribs are considered flat bones.
The function of the ribcage is to protect the heart and lungs. It also anchors important muscles that work the lungs during breathing (respiration). The diaphragm and intercostals muscles attach to the ribcage drawing it up and out when we inhale. (Inhale and feel your ribcage rise and grow). This expands the lungs (which are also attached to the ribcage through a double lining called the pleura) and brings air into the lungs (inhale). When the muscles relax, the ribcage sinks and gets smaller again and we breathe out (exhale).
CITING RESEARCH REFERENCES
Amsel, Sheri. “Skeletal System.” The Ribcage (Bony Thorax). Exploring Nature Educational Resource. © 2005 - 2009.
November 19, 2009. <http://exploringnature.org/db/detail.php?dbID=24&detID=29>