Flail chest occurs when contiguous ribs each show multiple fractures. It usually occurs after severe blunt force has been applied to the chest and often indicates significant underlying pulmonary contusion.


A flail segment requires:

(1) 2 or more contiguous ribs

(2) each with 2 or more points of fracture


Clinical appearance: Paradoxical motion of the affected chest wall segment during respiration.


Types based on location:

(1) sternal: separation of the sternum from the surrounding ribs

(2) anterior segment

(3) lateral segment

(4) posterior segment: This is rarely clinically apparent because of the muscular support over the back.



• Fractures of the first 2 ribs

• I am not sure if fractures to the 11th or 12th ribs would contribute to a flail chest. I have included the 11th ribs in the implementation, but this is subjective.

• While it usually takes significant blunt trauma to cause a flail chest, patients with underlying bone disease may develop flail chest after relatively minor injuries.


Other injuries to look for in a patient with flail chest:

(1) pneumothorax

(2) hemothorax

(3) intra-abdominal injuries


To read more or access our algorithms and calculators, please log in or register.