[2] It can result from blunt or penetrating trauma to the neck or chest,[3] inhalation of harmful fumes or smoke, or aspiration of liquids or objects.

[5] Of those people with TBI who die, most do so before receiving emergency care, either from airway obstruction, exsanguination, or from injuries to other vital organs.

[7] Early diagnosis is important to prevent complications, which include stenosis (narrowing) of the airway, respiratory tract infection, and damage to the lung tissue.

Diagnosis involves procedures such as bronchoscopy, radiography, and x-ray computed tomography to visualize the tracheobronchial tree.

[3] Coughing may be present,[11] and stridor, an abnormal, high-pitched breath sound indicating obstruction of the upper airway can also occur.

[14] Injuries to the tracheobronchial tree within the chest may occur due to penetrating forces such as gunshot wounds, but are more often the result of blunt trauma.

[6] TBI due blunt forces usually results from high-energy impacts such as falls from height and motor vehicle accidents; the injury is rare in low-impact mechanisms.

[18] TBI resulting from tracheal intubation (insertion of a tube into the trachea) is rare, and the mechanism by which it occurs is unclear.

[19] However, one likely mechanism involves an endotracheal tube catching in a fold of membrane and tearing it as it is advanced downward through the airway.

[20] Excessive pressure from the cuff of an endotracheal tube can reduce blood supply to the tissues of the trachea, leading to ischemia and potentially causing it to become ulcerated, infected, and, later, narrowed.

[4] The mucosal lining of the trachea may also be injured by inhalation of hot gases or harmful fumes such as chlorine gas.

[2] When this pressure exceeds the elasticity of the tissues, they burst; thus the membranous part of the trachea is more commonly affected by this mechanism of injury than cartilaginous portions.

The trachea is situated between the lower end of the larynx and the center of the chest, where it splits into the two bronchi at a ridge called the carina.

[21] The bronchi split into smaller branches and then to bronchioles that supply air to the alveoli, the tiny air-filled sacs in the lungs responsible for absorbing oxygen.

[17] Anatomical structures that surround and protect the tracheobronchial tree include the lungs, the esophagus, large blood vessels, the rib cage, the thoracic spine, and the sternum.

[2] If subcutaneous emphysema occurs and the hyoid bone appears in an X-ray to be sitting unusually high in the throat, it may be an indication that the trachea has been severed.

[14] Bronchial injuries are divided into those that are accompanied by a disruption of the pleura and those that are not; in the former, air can leak from the hole in the airway and a pneumothorax can form.

[29] Repair of extensive tears can include sewing a flap of tissue taken from the membranes surrounding the heart or lungs (the pericardium and pleura, respectively) over the sutures to protect them.

[3] Surgery to repair a tear in the tracheobronchial tree can be successful even when it is performed months after the trauma, as can occur if the diagnosis of TBI is delayed.

[5] Most late deaths that occur in TBI are attributed to sepsis or multiple organ dysfunction syndrome (MODS).

[29] People with a narrowed airway may develop dyspnea, coughing, wheezing, respiratory tract infection, and difficulty with clearing secretions.

[22] Infected lung tissue distal to a stricture can be damaged, and wheezing and coughing may develop due to the narrowing.

[22] It is difficult to determine the incidence of TBI: in as many as 30–80% of cases, death occurs before the person reaches a hospital, and these people may not be included in studies.

[2] Another study of blunt chest trauma revealed an incidence of only 0.3%, but a mortality rate of 67% (possibly due in part to associated injuries).

[6] The incidence of iatrogenic TBI (that caused by medical procedures) is rising, and the risk may be higher for women and the elderly.

[22] The number of people reaching a hospital alive has increased, perhaps due to improved prehospital care or specialized treatment centers.

[10] Injuries that may accompany TBI include pulmonary contusion and laceration; and fractures of the sternum, ribs and clavicles.

[5] However, in 1871 a healed TBI was noted in a duck that had been killed by a hunter, thus demonstrating that the injury could be survived, at least in the general sense.

[22] In 1873, Seuvre made one of the earliest reports of TBI in the medical literature: a 74-year-old woman whose chest was crushed by a wagon wheel was found on autopsy to have an avulsion of the right bronchus.

[5][6] In 1931, a report made by Nissen described successful removal of a lung in a 12-year-old girl who had had narrowing of the bronchus due to the injury.