The chest cavity contains vital organs and is protected by a bony rib cage. The ribs are connected to each other by several layers of muscles which assist with breathing. They are also attached to the spine for added stability. A rib fracture, simply put, is a break in the rib. Rib fractures that are single and non-displaced are classified as hairline fractures or simple fractures. Ribs usually fracture at the point of impact or in the back where structurally they are weakest. More complex fractures can cause the edges of the bone to become misaligned or displaced. A serious condition involved with rib fractures is called ‘flail chest’. It occurs when multiple adjacent ribs are broken in multiple places, separating a segment which is free-floating and moves independently. The most common ribs fractured are the 7th through 10th ribs. Fractures of the first and second ribs are rare but may be associated with serious damage to the brachial plexus of nerves, the subclavian vessels or associated with head, facial or thoracic aorta injuries. A lower rib fracture is more likely associated with injuries to the diaphragm, liver or spleen.
The most common mechanism causing rib fractures is blunt trauma (i.e. automobile accidents, falls from height, assault, or even severe coughing). Blunt trauma causes rib fractures by exerting direct pressure on the rib causing it to break. Approximately 10% of all patients admitted for blunt chest trauma have one or more rib fractures. Although the injury mechanism itself is an important consideration when discussing rib fractures; patient specific considerations are also important. Patients with advanced age, osteoporosis or osteopenia have an increased risk of number and severity of fractures.
Rib fractures are typically diagnosed on chest x-ray and the severity of the fracture is easily seen. Simple (non-displaced) fractures appear as cracks in the rib or a jagged edge. Displaced fractures appear to lack contour along the edge of the rib on x-ray. Floating segments of ribs, known as a flail chest, can also be easily seen on x-ray. Other imaging modalities such as CT scans also diagnose rib fractures and are more sensitive to identify them. CT scans are useful to determine if underlying lung injury is present, known as a contusion, or to identify if air has escaped the lung as a pneumothorax.
The most common symptom of rib fractures is pain. Pain is typically elicited with breathing or coughing. If the fractures are complex, the patient may suffer from additional damage to underlying structures. The sharp fractured end of the rib can puncture the lung, causing air leakage, a condition called a pneumothorax, which is potentially life threatening. In addition to pain, shortness of breath and decreased oxygen content in the blood can result from these injuries. A flail chest is invariably accompanied by pulmonary contusion, a bruise of the lung tissue that can result in a clinical entity called acute lung injury. In its most severe form, acute lung injury can lead to a life threatening entity called adult respiratory distress syndrome (ARDS). Respiratory failure is usually caused by the underlying pulmonary contusion but not by the anatomic flail chest itself. In addition, the flail segment moves in the opposite direction as the rest of the chest wall because of the ambient pressure in comparison to the pressure inside the lungs. This so-called "paradoxical motion" can increase the work and pain involved with breathing.
There is no specific treatment for rib fractures, but various supportive measures can be taken. Simple rib fractures can be managed with pain management alone. Patients are encouraged to use an incentive spirometer, a medical device used to help improve the function of lungs, and control pain with medication as per their physician. If the pain is not relieved with medication alone other methods of pain relieve may be considered, eg. nerve blockage. When patients sustain multiple rib fractures, oxygen support in addition to pain medication is sometimes required. A pneumothorax usually necessitates a procedure to drain the air out of the chest with a chest tube. A flail chest can significantly affect the mechanics of breathing and may require ventilatory support to improve blood oxygen concentration and possibly repair of the fractures with metal plates.
Authors: Jennifer A. Serfin, MD, W. Alan Guo, MD, PhD, FACS