Chest trauma or injury is a significant cause of disability and mortality worldwide, accounting for 10 percent of hospital admissions and 25 to 50 percent of deaths related to trauma. One life-threatening condition that can result from blunt chest trauma, such as a serious fall or car crash, is flail chest, which is marked by a portion of the rib cage being separated from the rest of the chest wall.

An Instagram account called Medical Doctors Worldwide posted a graphic clip demonstrating what flail chest actually looks like. It shows a man with a bruised left chest that’s moving in the opposite direction to the rest of the chest wall. According to the caption posted by the account, this is due to “the ambient pressure in comparison to the pressure inside the lungs, it goes in while the rest of the chest is moving out, and vice versa.” The resulting experience, often called paradoxical movement, is both painful and takes more effort with each breath, hampering the process of inhaling and exhaling.

According to the University of Rochester Medical Center, flail chest is diagnosed when three or more adjacent ribs are broken in two or more places. However, paradoxical movement of the chest is usually the most telling symptom and an obvious sign that the affected portion of the chest wall “is not assisting with the breathing function.”

Medical Doctors Worldwide said the condition is usually accompanied by a pulmonary contusion, or a bruise of the lung that can interfere with blood oxygenation. “Often, it is the contusion, not the flail segment, that is the main cause of respiratory problems in people with both injuries,” they said. When faced with the condition, doctors should stablilize the chest wall, then treat injuries in and around the chest.