Flail chest is multiple fractures in ≥ 3 adjacent ribs that result in a segment of the chest wall separating from the rest of the thoracic cage; it is a marker for injury to the underlying lung. Symptoms include severe chest pain with movement or breathing, dyspnea, and sometimes hemoptysis of the trunk (including coughing or deep breathing) and tenderness over the injured rib on examination. Diagnosis is by observing the paradoxical motion of the flail segment during breathing; chest radiograph and/or CT are typically performed to confirm rib fracture and evaluate for additional injuries. However, this motion may be difficult to see if inspiratory depth is limited by pain or obtundation due to other injuries. Treatment is with analgesics and sometimes with mechanical ventilation or surgery.
A single rib may fracture at more than one location. If multiple (3 or more) adjacent ribs fracture in ≥ 2 places, the breaks in each rib result in a flail segment of chest wall that is not mechanically connected to the rest of the thoracic cage. If this flail segment moves paradoxically (ie, outward during expiration and inward during inspiration—see figure Flail Chest), it is called flail chest.
Patients with flail chest typically present with severe chest pain that worsens with inspiration, coughing, or movement; dyspnea; tachypnea; coughing; and sometimes hemoptysis. They are at high risk for respiratory complications, mainly because the large amount of force required to cause a flail chest typically causes a significant underlying pulmonary contusion. In addition, the paradoxical motion of flail chest increases the work of breathing, and chest wall pain tends to limit deep inspiration and thus maximal ventilation.
Flail Chest
Diagnosis of Flail Chest
History and physical examination
Chest radiograph
Chest CT
Diagnosis of flail chest is based primarily on history and physical examination, ideally by observing the paradoxical motion of the flail segment during breathing. However, this motion may be difficult to see if inspiratory depth is limited by pain or obtundation due to other injuries. The paradoxical motion does not occur if the patient is mechanically ventilated, but the flail segment may be identified by its more extreme outward movement during lung inflation. Palpation can often detect crepitus of the flail segment and confirm abnormal chest wall motion.
Chest radiograph is typically performed as an initial study to check for concomitant injuries (eg, pneumothorax, pulmonary contusion). However, chest radiograph has only a 50% sensitivity for detecting rib fracture (1). Chest CT, with or without contrast, is the diagnostic imaging modality of choice because it is more sensitive than radiograph for diagnosing rib fracture and may also be able to delineate location and degree of displacement of the rib fractures. CT is also part of the evaluation for additional injuries.
Diagnosis reference
1. Expert Panel on Thoracic Imaging:, Henry TS, Donnelly EF, et al. ACR Appropriateness Criteria® Rib Fractures. J Am Coll Radiol. 2019;16(5S):S227-S234. doi:10.1016/j.jacr.2019.02.019
Treatment of Flail Chest
Supportive care
Sometimes mechanical ventilation
Sometimes rib fracture repair
Humidified oxygen is given to patients with flail chest. Analgesics may help improve ventilation by decreasing pain during breathing, but ventilation may need to be supported mechanically. Volume status should be closely monitored because harm can result from either hypovolemia (due to lung hypoperfusion) or hypervolemia (due to pulmonary edema) (1). In patients with flail chest, early surgical stabilization of rib and sternal fractures appears to reduce the risk of pneumonia, length of hospital stay, duration of mechanical ventilation, and death (2, 3).
Treatment references
1. Simon B, Ebert J, Bokhari F, et al. Management of pulmonary contusion and flail chest: An Eastern Association for the Surgery of Trauma practice management guideline. J Trauma and Acute Care Surgery. 2012;73(5 Suppl 4):S351-S361. doi: 10.1097/TA.0b013e31827019fd
2. Kwon J, Zakhary B, Coimbra BC, et al. Early surgical stabilization of multiple rib fractures and flail chest is associated with better outcomes compared with nonoperative management. J Trauma Acute Care Surg. 2025;99(6):859-867. doi:10.1097/TA.0000000000004770
3. Bauman ZM, Tian Y, Doben AR, et al. Chest Wall Injury Society guidelines for surgical stabilization of rib fractures: Indications, contraindications, and timing. J Trauma Acute Care Surg. 2025;99(4):522-532. doi:10.1097/TA.0000000000004750
