Overview
Thoracic trauma may present as an isolated rib fracture, a chest contusion, or a laceration; however, significant thoracic trauma often involves multiple organ systems and several anatomic regions.
The chest trauma that results from a motor vehicle accident may result in injury to the sternum, the ribs, and the heart, aorta, and lungs. Multiple injuries often occur in people who are involved in traffic accidents, and rib fractures are among the most common of these injuries, with an occurrence as high as 60%. Radiography of the chest should be a routine part of autopsies of patients who die of injuries that result from traffic accidents.
Radiographs can depict bony trauma, and rib fractures are among the most commonly identified injuries to the chest. Injuries to the chest wall may involve the pleural space, lungs, extrapleural space, mediastinum, heart and great vessels, spine, and shoulders.
The location of specific rib fractures is an important indicator of related injury. Rib fractures can be studied as 3 distinct patterns according to their location (see the images below): (1) fractures of the first rib and those of the second to fourth ribs, (2) fractures of the fifth to ninth ribs, and (3) fractures of the 10th to 12th ribs. These 3 distinct patterns of rib fractures represent unique pathophysiology and associated morbidity. A rib score has been proposed to predict adverse pulmonary outcomes.
Frontal image of the rib cage. Ribs 1-12 demonstrate the variable shape of the upper 9 ribs. The 12th rib does not articulate anteriorly. The sternum consists of the manubrium (M), the body (S), and the xiphoid (X). The ribs articulate with the sternum via the costochondral (CC) junction. C = clavicle.
Posterior image of the thorax. The ribs are numbered 1-12. The clavicle (C) and scapula (S) are often involved in injuries that include rib fractures.
Pathophysiology
Fractures of the first rib
Fractures of the first rib are rare. The significance of a first rib fracture is the association with cervical spine trauma, multiple rib fractures or life-threatening vascular injuries. Historically, fractures of ribs 1-3 have been associated with injuries of the brachial plexus and major vessels. CT angiography (CTA) should be considered in stable patients with first rib fractures if there are absent or decreased upper extremity pulses, regional hemorrhage, and/or brachial plexus injury. Additional criteria for angiography include displacement of bone fragments and multiple thoracic injuries.
Fractures of the first rib imply a violent force; this pattern of fractures may signify injury to the adjacent subclavian vein and brachial plexus. Isolated first rib fractures are seen in association with cranial and maxillofacial injuries and are probably secondary to avulsion of the first rib by its muscular attachment rather than direct trauma to the rib, which is relatively protected. Surfer’s rib is an isolated first-rib fracture and occurs in surfers who perform the lay-back maneuver.
Fractures of the fifth to ninth ribs
Fractures of the fifth to ninth ribs can be single or multiple. Multiple fractures can present as flail chest, which is present when paradoxical respiratory movement occurs in a segment of the chest wall. This type of fracture requires at least 2 segmental fractures in each of 3 adjacent ribs, the costal cartilages, or the sternum (see the image below). Posterior flail segments are easier to manage clinically because of the presence of strong muscular and scapular support and because of a patient’s natural tendency to lie with his or her back against the mattress.
Image depicting multiple fractures of the left upper chest wall. The first rib is often fractured posteriorly (black arrows). If multiple rib fractures occur along the midlateral (red arrows) or anterior chest wall (blue arrows), a flail chest (dotted black lines) may result.
Image of the common middle rib. The common middle rib consists of the neck that is closest to the thoracic spine with an articular tubercle, the angle of which is a curved portion of the rib, and the distal body.
An inward displacement of the rib fracture fragments at the time of the injury may lacerate the lung parenchyma and produce a pneumothorax, with a possible hemothorax. Although lung trauma is generally seen immediately, the occurrence of a pneumothorax and hemothorax may be delayed for hours after the injury. Hemothorax of a significant degree secondary to rib fractures is usually the result of laceration of an intercostal artery rather than bleeding from the lung. The hemothorax resulting from a laceration of an intercostal artery can be life threatening.
A spontaneous fracture of a midthoracic rib should alert the clinician for an underlying metastasis, multiple myeloma, or hyperparathyroidism.
Fractures of the tenth to the twelfth ribs
Hemorrhage around and within the adrenal glands represents a risk that is associated with fractures of the lower ribs. Fractures of the lower ribs are also commonly associated with visceral injury to the kidneys and the spleen. Associated lumbar and thoracic vertebral spinal injuries occur because of the proximity of the transverse spinous processes to the lower thoracic and upper lumbar spine.
Pneumothorax
A pneumothorax is a common sequela of blunt trauma. Fracture fragments that lacerate the lung parenchyma can cause bleeding into the pleural cavity and result in a pneumothorax (see the image below).
Semi-erect anteroposterior (AP) chest radiograph in a patient with a nondisplaced posterior fracture of the left 10th rib. A small, apical pneumothorax (black arrow) is present on the left, and there is volume loss in the left lower lobe (white arrow).
The incidence of a pneumothorax is not as high with 1 rib fracture, but the risk increases as the number of broken ribs increases (see the images below).
Supine anteroposterior (AP) chest radiograph shows the presence of a right tension pneumothorax, which has displaced the trachea to the right (blue arrow). A displaced right lower rib fracture is present in the right posterolateral aspect of the chest (black arrow).
Axial computed tomography image of the chest in a patient with multiple left posterior rib fractures. A large left pneumothorax is present (arrows).
Axial computed tomography image of the chest in a patient with left posterior rib fractures. The left pneumothorax (white arrows) is associated with a displaced posterior left rib fracture (black arrow). Secondary effects on the left lung include a pulmonary contusion and volume loss.
In a retrospective study, Miller and Ghanekar found that significant solid organ injury was 3.5 times more common in patients who suffered blunt trauma and had a pneumothorax than in patients without a pneumothorax. In addition, the authors found that the association of rib fractures with a pneumothorax resulted in a larger number of visceral lacerations by fragments of bone. They recommended that because a large proportion of pneumothoraces found with CT scanning are not visualized on a portable chest radiograph, clinicians should look for indirect signs of pneumothorax, such as the presence of rib fractures and subcutaneous air.
Hemothorax
The incidence of hemopneumothoraces in patients with rib fractures is 30%. A hemothorax is usually the result of a lacerated intercostal artery; however, bleeding from broken ribs usually stops before a sufficient volume is lost and before emergency thoracotomy is required. Note: About 400-500 mL of blood may be hidden by the diaphragm on an upright chest radiograph, and 1 L or more of blood may be overlooked on a supine image.
The bleeding may be delayed or may recur after several days. In a review by Simon et al, 12 cases of delayed hemothorax were identified, and 92% of those occurred in patients with multiple or displaced rib fractures.
The presentation of hemothorax in these cases occurred between 18 hours and 6 days after the injury. Eleven of the affected patients complained of new-onset pleuritic chest pain and dyspnea; the symptoms were similar to those of a pulmonary embolism.
Pulmonary contusion
Rib fractures are associated with pulmonary contusions in 20-40% of cases. The injury is characterized by capillary disruption that results in the presence of intra-alveolar and interstitial hemorrhage, edema, protein, and fluid obstruction of the small airways with leukocyte infiltration. Serial chest radiographs obtained beginning right after the injury show a fluffy infiltrate that progresses in extent and opacity over 24-48 hours.
Pulmonary contusions are often a part of a major chest injury that includes 1 or more fractures of the thoracic cage, a pneumothorax, and a hemothorax. The contusions may occur by the transmission of force through the chest wall with minimal fractures of the ribs or sternum; this mechanism is especially seen in the young in whom there is greater flexibility of the rib articulations allowing for more lung compression in the absence of a fracture. In middle-aged or elderly patients, pulmonary contusions are usually accompanied by multiple rib fractures. A rib score has been proposed to predict adverse pulmonary outcomes.
Aortic injuries
The idea that thoracic cage injuries are predictive of acute traumatic aortic tears is controversial. A study by Lee et al concluded that no clinically relevant correlation exists between these injuries and acute traumatic aortic tears.
The authors also concluded that isolated upper rib fractures are not an indication for aortic angiography; however, first rib and second rib fractures may indicate a severity of trauma associated with facial, spinal, and brachial injuries.
An aortic injury that is related to blunt trauma is usually due to the transmission of a shearing force at the ligamentum arteriosum or due to the forceful compression of the aortic root. However, there have been case reports that describe fractured ribs puncturing the aorta. One such case involved a posterior fracture of the left sixth rib that lacerated the aorta 3 days after the trauma occurred.
Flail chest
A flail chest is present when a paradoxical respiratory movement occurs in a segment of the chest wall, the result of at least 2 segmental fractures in each of 3 adjacent ribs or costal cartilages (see the images below). The incidence of flail segments is 10-15% in patients with major chest trauma. More severe injuries, such as closed head injury and intrathoracic injury, are common in the presence of a flail chest.
Anteroposterior (AP) supine chest radiograph that was obtained upon a patient’s arrival in the emergency department after a serious automobile accident. Although rib fractures are identified along the left lateral chest wall (black arrows), the transportation bed created superimposed metal artifacts (blue arrows) that obscure visualization of possible other rib fractures along the chest wall.
Supine anteroposterior (AP) chest radiograph that was obtained after the removal of metal artifacts along the left chest wall. Multiple posterolateral rib fractures are noted on the left (arrows; Note: White and black arrows were used for easy visualization due to the dark and light areas of the lungs).
Multiple fractures of the upper chest with a dislocation of the clavicle are also associated with extrathoracic lung herniation.
However, in most cases, no chest-wall defects are present. Flail chest may lead to respiratory failure secondary to the pulmonary contusion and pain during inspiration.
Epidemiology
In a large group of Japanese patients with rheumatoid arthritis who were followed for a mean duration of 5.2 years, 13.5 % reported incident fractures. Rib fractures were the most common fractures in men. The most common fractures in women were clinical vertebral fractures, followed by rib fractures.
Clinical details
First rib fractures have often been described as having a high association with serious or lethal spinal or vascular injuries. While first rib fractures have a high association with spinal fractures and are associated with multisystem injuries, the occurrence of first rib fractures is not always associated with increased morbidity and mortality. The presence of a first rib injury requires a multidisciplinary approach. CT of the spine and chest allows for an early diagnosis. Appropriate treatment and observation in the intensive care unit may prevent further morbidity and/or mortality.
The number of rib fractures correlates with mortality in adult trauma patients, rising sharply in patients with more than 6 fractured ribs. In a study of pediatric patients (19</ref>
The association of lower rib fractures with pelvic fractures has been associated with a higher incidence of solid organ injury.
Differentials
Considerations in Pediatric Trauma
Initial Evaluation of the Trauma Patient
Surgical Therapy for Penetrating Abdominal Trauma
Preferred examination
The patient’s medical history and physical examination findings should suggest the diagnosis of a rib fracture. The primary signs and symptoms are a pleuritic-type chest pain and tenderness over fracture site. When 2 or more adjacent ribs are fractured, especially if they are broken in more than 1 place, examination alone should be enough to enable a presumptive diagnosis of a rib fracture.
The standard chest radiograph is useful in the recognition of preexistent or coexistent disease. The routine radiographic examination of the sternum includes the frontal prone and rotated views in an off-lateral projection. However, approximately 50% of all rib fractures go undetected during screening chest radiography (see the first 2 images below).
The examination of suspected rib fractures should include the acquisition of erect posteroanterior (PA) and oblique radiographs of the chest (see the third image below). An erect frontal examination of the chest is useful in the detection of a pneumothorax, pulmonary contusion, or pleural effusion.
Anteroposterior (AP) chest radiograph in a patient who presented with severe left chest wall pain after a minor fall. No rib injury is apparent.
Anteroposterior (AP) radiograph of an elderly female patient with severe left chest wall pain after a minor fall. This image demonstrates a left lateral rib fracture (arrow) that is not seen on the standard AP chest radiograph.
This detailed oblique radiograph shows 2 rib fractures (arrows) that are not depicted on anteroposterior (AP) chest radiographs.
Each oblique projection is intended to depict the entire rib. The PA chest radiograph alone is ineffective in the identification of incomplete or minimally displaced rib fractures; the lower ribs may be obscured by the upper abdominal organs. If a lower rib fracture is suspected, a radiographic technique is required that centers an AP radiograph of the lower portion of the chest and upper abdomen on the upper lumbar spine film.
If the patient remains symptomatic despite a negative initial radiograph, a repeat radiograph of the ribs, acquired with a standard technique, often demonstrates the signs of early healing of a rib fracture. If the identification of occult rib fractures is clinically important, as in a case of suspected child abuse or for medicolegal reasons, radionuclear bone scanning with technetium-99m methylene diphosphonate (99mTc MDP) is often successful. A delay of several days should be allowed after an acute trauma to increase the sensitivity of radionuclear imaging for a rib fracture.
Rib fractures may be seen by using bone window settings on a chest CT scan; however, an occult rib fracture is not an indication for thoracic CT scanning.
Limitations of techniques
In obese patients and in older patients with osteoporosis, the evaluation for uncomplicated rib fractures is often difficult to perform with standard radiographs.
Greenstick fractures may not be seen on initial chest radiographs because of the nondistracted nature of the injury.
Cartilage fractures and costochondral separations are not seen on routine chest radiographs; several weeks may pass before such injuries are visible on chest radiographs. However, the fractures may be indirectly seen following the development of periosteal reaction around the fractures.
Radiologic intervention
Radiologic intervention in cases of rib trauma generally represents emergency treatment of the complications of chest-wall injuries (pneumothoraces) or the control of hemorrhage. Angiography may be used as a diagnostic technique in cases in which findings in the aortic arch and anterior mediastinum remain in doubt.
Treatment
Bansidhar et al found that 93% of patients with clinical rib fractures are able to resume their daily activities without disability.
As a result, the authors did not recommend routine chest radiographic follow-up in addition to physical examination except in the presence of clinical deterioration.
Adequate pain control, rapid mobilization, and meticulous respiratory care can prevent respiratory complications in patients with rib fractures. An adequate oral analgesic or an intercostal nerve block plus an oral analgesic should provide reasonable pain relief. Epidural analgesia is becoming the standard of care for pain management in patients with multiple rib fractures.
In a study in which morphine patient-controlled analgesia (PCA) was compared with thoracic epidural analgesia involving bupivacaine and fentanyl, the latter provided more adequate pain control.
In another study regarding the effectiveness of intrapleural analgesia for blunt trauma of the chest wall, this treatment did not significantly differ from placebo.
Furthermore, the investigators did not recommend intrapleural analgesia for pain management in patients with rib fractures.
Rapid mobilization can include oscillation therapy or body positioning in patients that are on bed rest or who are intubated. This mobilization can involve the patient’s ambulating, sitting up in bed, or getting out of bed to move into a chair. Respiratory care entails incentive spirometry, pulmonary toilet, and even mechanical ventilation, when indicated. In splinting the rib fractures, adhesive strapping or chest binders should be avoided in all patients except the very young.
If the management of multiple rib fractures is complicated by reducing lung function, the chest wall can be stabilized by the use of plates held in position by multiple screws (black arrows).
The treatment of multiple rib fractures includes the option of alignment and fixation of the fractures if respiration is compromised. After alignment, a plate was applied to each of four displaced rib fractures, held in position by multiple screws (white arrows).
Patient education
For patient education information, see the Fractures and Broken Bones Center, as well as Collapsed Lung (Pneumothorax), Broken Shoulder Blade, Broken Collarbone, and Wilderness: Chest Injuries.