Most fractured ribs heal within a month or two, states Mayo Clinic. While the rib is healing, it is very important to control pain so the patient can breathe comfortably. When a cracked rib prevents deep breathing, lung conditions such as pneumonia may occur.
Most rib injuries are cracks rather than complete breaks in the bone, says Mayo Clinic. They usually are caused by injuries to the chest from accidents, falls or sports. These cracks are not as dangerous as actual breaks to the ribs, in which sharp edges of the bone may penetrate blood vessels or internal organs.
Broken ribs can cause serious complications, especially if multiple ribs are broken or the broken ribs are close to vital organs, explains Mayo Clinic. The three ribs at the top of the rib cage are very close to the blood vessels around the heart. A jagged edge of one of these ribs can cut the aorta or another vessel. The middle ribs lie close to the lungs, and a sharp edge can cause a lung injury. While the bottom two ribs are more flexible than the other ribs and are less easily broken, a break in one of these can pierce the spleen, liver or kidneys.