ANATOMY & PHYSIOLOGY A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z                    HOME ABOUT CATEGORIES SITE MAP COPYRIGHT ADVERTISE CONTACT entire Web this site rib-cage A bony framework that protects the heart, lungs, and other underlying organs. The rib-cage is made up of three types of bone – the sternum (breastbone), 12 pairs of ribs, and 12 thoracic vertebrae. All of the ribs attach to the spinal column, but only the top seven pairs connect to the sternum. These are called true ribs and are connected to the sternum by strips of cartilage known as costal cartilage. The next three pairs of ribs are known as false ribs. Instead of attaching directly to they sternum, they all attach to the lowest true rib. The last two pairs of ribs are called floating ribs and attach only to the spine. Upon inhalation, muscles between the ribs, called intercostal muscles, lift the ribcage helping the lungs to expand. Upon exhalation, the rib-cage moves down, squeezing air out of the lungs. Related category    • ANATOMY AND PHYSIOLOGY Also on this site: Encyclopedia of Alternative Energy & Sustainable Living Encyclopedia of History Transport Concepts & Designs (partner site) BACK TO TOP