flail chest

Last reviewed 01/2018

The function of the ribs is to provide a framework upon which muscles act to generate breathing movements. Breathing movements result in pressure differences between the environment and the thorax. These pressure differences are resisted by the rib cage.

A direct blow to the chest may result in a localised disruption in the integrity of the rib cage. Most commonly, double fractures of the ribs result in a section of chest wall which cannot resist the pressure gradient generated during breathing.

The result is "paradoxical respiration":

• the flail segment is drawn in during inspiration
• the flail segment is pushed out during expiration

The loss of tidal volume may precipitate respiratory failure.