A Chance fracture is a flexion injury of the spine, first described by GQ Chance in 1948. It consists of a compression injury to the anterior portion of the vertebral body and a transverse fracture through the posterior elements of the vertebra and the posterior portion of the vertebral body. It is caused by violent forward flexion, causing distraction injury to the posterior elements.
The most common site at which Chance fractures occur is the thoracolumbar junction (T12-L2) and midlumbar region in pediatric population. This fracture initially became known as a "seat belt injury" due to its association with the sudden forward flexion that occurs when one is involved in a head-on automobile collision while being restrained by a lap belt. With the advent of both lap and shoulder belts in the 1980s, Chance fractures have become less common especially now that lap belts are almost phased out.
Up to 50% of Chance fractures have associated intraabdominal injuries. Injuries associated with Chance fractures include fractures of the pancreas; contusions or lacerations of the duodenum; and mesenteric contusions or lacerations.