Rib fractures are some of the most common thoracic injuries, but diagnosing them can be difficult because reliable clinical examination findings are lacking and radiographs are specific but not very sensitive. Certain types of rib fractures are associated with an increased risk of organ injury, and up to 50% are related to significant pulmonary trauma. Primary care providers must remain alert to the possibility of associated serious injuries such as pneumothorax, hemothorax, and vascular or abdominal organ laceration in the management of rib fractures. The principal goal in evaluating rib fractures is to detect complications. In the absence of complications, the goal is pain relief. Rib fractures in children after reportedly minor trauma should raise suspicion of child abuse.
The rib cage consists of true ribs and false ribs. The true ribs (1 to 7) have cartilage at the end of the ribs that attach directly to the sternum. The false ribs (8 to 12) attach to the costochondral cartilage of the superior rib. Fractures may occur anywhere along the rib cage but are somewhat more common in the posterior and middle third of the fourth through the ninth ribs. Fractures in the lateral aspect of the ribs are more common because they have less protection from the overlying chest musculature. Fractures in the upper ribs suggest that the patient has experienced a significant degree of trauma because the ribs are well protected by surrounding musculoskeletal structures, and the ribs are short and broad. Fractures in this location may be associated with arterial and bronchial trauma. Fractures of the lower ribs are associated with upper abdominal organ injury such as liver and spleen lacerations.
Mechanism of Injury
Rib fractures are the most common anatomic deformity resulting from blunt trauma but are rarely life threatening. Whereas blunt trauma to the chest is the most common cause of injury in rib fractures, less common causes include stress from severe or prolonged coughing and overuse stress in certain sports such as rowing, baseball (pitching), and golf. Rib stress fractures are discussed at end of the chapter in greater detail. Rib fractures can result from pathologic processes such as cancers that metastasize to bone such as breast, prostate, and renal cancer.
Rib Fractures after Trauma
Because the severe pain that accompanies a rib contusion is indistinguishable from that caused by a fracture, clinical impression is unreliable in identifying a rib fracture. Point tenderness, splinting, and referred pain on chest compression are common physical findings, but they are not specific enough to indicate a fracture. Decreased breath sounds may reflect splinting but could also be a sign of more significant injury (e.g., pneumothorax) and warrant further evaluation with radiographs.
The main reason to obtain a routine posteroanterior (PA) and lateral chest radiograph is to look for signs of intrathoracic complications of rib fractures such as pneumothorax or hemothorax. Although its role has been called into question, chest radiography is still standard practice in the emergency department evaluation of victims of major trauma. Trauma patients suspected of having a significant intrathoracic injury should undergo a computed tomography (CT) scan of the chest. A follow-up, two-view chest radiograph is recommended 6 hours after the initial evaluation to rule out a delayed hemothorax or pneumothorax. After high-energy injuries, multiple fractures in adjacent ribs usually occur. A flail chest results when three or more adjacent ribs fracture in two separate places on the same rib, creating a free-floating segment. Rib fractures are often detected coincidentally during the course of CT evaluation of the traumatized chest.
It is usually unnecessary to obtain dedicated rib films in addition to a standard chest series when evaluating a patient with a suspected rib fracture. Whereas routine chest radiographs demonstrate major intrathoracic complications of rib fractures, they are insufficient to detect all rib fractures. The routine chest radiograph allows for an excellent view of the posterior portion of the ribs above the diaphragm, but it does not adequately portray the lateral portion of the ribs. Lateral rib fractures must be significantly displaced before they can be detected on a routine chest radiograph. The anterior and posterior portions of the ribs can be seen in profile (the best way to see rib fractures) on the standard PA view. An oblique view of the ribs must be obtained to view the lateral portion of the ribs. A rib series is only indicated if suspicion is high for multiple fractures or pathologic fractures not apparent on plain radiographs.
A nondisplaced rib fracture is typically seen as a vertical or oblique fracture line with a slight offset that is more easily identified at the superior margin ( Figure 18-1 ). Nondisplaced or minimally displaced rib fractures may be detected more easily by looking for the surrounding soft tissue density of the hematoma that is usually associated with the fracture ( Figure 18-2 ). Rib fractures are often more obvious on follow-up radiographs because of displacement at the fracture margins caused by respiratory motion ( Figure 18-3 ). Nondisplaced fractures may only appear as callus at the fracture site 10 to 14 days after injury.