Though the rib cage is strong, there is a limit to which it can withstand force. If the chest is hit with a great force, the ribs can develop cracks or get fractured. One could even suffer from a rib cartilage injury due to such an impact. The rib cartilage can develop tears. If the impact is greater, the cartilage may even separate from the ribs. This condition is medically referred to as costochondral separation. Here's some information on the symptoms as well as the treatment of rib cartilage injuries.