The exact incidence of rib fractures is unknown, but experts estimate a regional trauma center can expect 10% of all trauma admissions to have rib fractures. Fractures result from a direct or indirect blunt force or crush injury. Motor vehicle crashes (MVCs) and falls are the most common mechanisms of injury associated with rib fractures in the adult population. In the pediatric population, rib fractures are commonly the result of intentional injury in younger children, with recreational/athletic injuries being more common in the older pediatric population.

Rib fractures may occur in a single rib or multiple ribs and occur most often in the fourth through tenth ribs. These fractures are not considered life-threatening but can be associated with potentially life-threatening injuries to the underlying organs (most commonly the lungs). The patient often experiences pain/tenderness at the fracture site, so respirations are shallow (splinted) to avoid moving the chest wall. Fragments of fractured ribs can also act as penetrating objects, leading to the formation of a hemothorax or a pneumothorax. Subcutaneous emphysema or crepitus may also be present. Chest radiographs assist with diagnosis but are only 70% sensitive for detecting rib fractures. Fractures that separate the sternum from costal cartilage are not evident on a radiograph.

Fractures of the first and second ribs are rare due to the protection granted to them by the clavicle. Significant blunt force is required to fracture these ribs; therefore associated injuries to the underlying structures, the great vessels, and brachial plexus must be considered. Other injuries associated with upper rib fractures include injuries to the clavicles, scapulae, trachea, and lungs. Lower rib fractures (9 through 12) are associated with injuries to the spleen, liver, kidneys, or other abdominal contents, depending on location of the fracture(s).

A flail chest is defined as fractures in two or more adjacent ribs in two or more places, or bilateral detachment of the sternum from costal cartilage (Figure 23-2). Mechanically a significant force diffused over a large area (i.e., the thorax) is usually required to create multiple anterior and posterior rib fractures. ⁴ Flail chest is usually associated with a fall, massive crush injury, or high-speed MVC. Flail chest commonly occurs in older adults secondary to their weakened structural components. A flail chest creates a free-floating, unstable segment that moves in opposition to normal chest wall movement. The flail segment moves in when the patient inspires and out with exhalation. The loss of coordinated chest wall movement results in hypoventilation of both lungs followed by atelectasis and eventually hypoxia. This injury is usually associated with an underlying pulmonary contusion that further compromises ventilation because of loss of pulmonary compliance, increased airway resistance, and decreased gas diffusion.

Diagnosis of flail chest is often made by direct observation—the affected area moves paradoxically from the rest of the chest. Muscular splinting of the chest immediately after injury may, however, mask a flail chest until hours later when intercostal muscles become fatigued and paradoxical movement becomes obvious, causing this diagnosis to be missed or delayed. 1. ^{and 4.} Paradoxical chest wall movement will not be demonstrated in the mechanically ventilated patient. Palpation of the chest wall may indicate abnormal motion and crepitus. The patient complains of pain and difficulty breathing. Plain chest radiographs may not be helpful because many times fractures are not visible. A computed tomography (CT) scan of the chest can provide significant information as to the number of ribs that are fractured and even early diagnosis of a pulmonary contusion; if there is any suspicion of involvement of the great vessels a CT angiography (CTA) should be performed. Blood gas analysis illustrates the severity of the hypoventilation caused by both the pulmonary contusion and the pain of the rib fractures and can be helpful as a baseline in assessing the need for mechanical ventilation. These values can also assist in the management of pain in these patients. ¹

Treatment consists of ensuring adequate oxygenation, judicious fluid administration, and pain management. Fluids are limited because of associated pulmonary contusion and potential development of acute respiratory distress syndrome (ARDS). Intubation and mechanical ventilation are not required for all patients, but patients should be monitored carefully for any change in respiratory status that indicates a need for more aggressive management (i.e., changes in respiratory rate, arterial oxygen tension, and work of breathing). ¹ Patients who require mechanical ventilation are usually managed with continuous positive end-expiratory pressure (PEEP); continuous positive airway pressure (CPAP) may successfully be used for some patients. Patient-controlled analgesia (PCA) pumps, oral/transdermal/intravenous pain medications, intercostal blocks, and indwelling epidural catheters form the mainstay of current pain management. Surgical stabilization is rarely used. ⁴ Although surgical management of patients with severe flail chest is at present controversial, surgical stabilization has been indicated in specific clinical situations, such as when the patient fails to wean from the ventilator once a partial resolution of the pulmonary contusion is achieved, or in patients with deteriorating pulmonary function despite aggressive clearance of bronchial secretions and adequate analgesia.

With the increased use of seat belts, shoulder restraints, and air bags in motor vehicles, there has been a decrease in the number of sternal fractures. Sternal fractures occur when tremendous force is applied to the chest, as with steering wheel impact, sporting injuries in which direct thoracic impact is sustained, or falls. Sternal fractures secondary to cardiac compressions during basic life support measures, or even stress fractures (as in weight lifters) do occur, but rarely. Occurrence is more common in the older adult population due to their inelastic/weakened bony thorax. The most common site of fracture is the junction of the manubrium and body of the sternum (angle of Louis, adjacent to the second intercostal space). ⁶ In addition to pain, a sternal fracture has significant potential for underlying cardiac and pulmonary injury, including pulmonary contusion, blunt cardiac injury, and pericardial tamponade.

The patient may experience dyspnea and localized pain with movement and may hypoventilate to avoid chest wall movement. Chest wall ecchymosis, sternal deformity, or crepitus may also occur. Treatment includes pain relief (as described above), a baseline electrocardiogram (ECG) to evaluate potential blunt cardiac injury, and serial patient examinations. If the fracture is displaced, operative reduction may be required. If cardiac symptoms are present, an echocardiogram may be obtained to evaluate myocardial performance. No surgical intervention is usually required. Patients are treated symptomatically.