Images in Clinical Medicine
Atloido-Occipital Dislocation in a Small Child after Air-Bag Deployment
N Engl J Med 2001; 345:1256October 25, 2001
- Article
Figure 1 A two-year-old girl riding in an automobile was involved in a low-speed collision in which the air bags deployed. At the time of the crash she was sitting unrestrained in the front passenger seat. She was apneic and unresponsive before the ambulance arrived. She was intubated at the scene, and resuscitation was instituted according to established guidelines. Except for numerous neck abrasions and burns, no other overt injuries were apparent on physical examination. A radiograph of the lateral cervical spine showed atloido-occipital dislocation (arrowheads), with a 4-cm gap between the occipital condyle and the superior articular facet of the atlas. Computed tomography of the head showed subarachnoid hemorrhage, marked cerebral edema, and an extraaxial hematoma within the epidural space and spinal canal surrounding the cord, with marked thinning — and, possibly, transection — of the spinal cord. The patient died hours later.
Since 1998 all new cars have come equipped with dual air bags that inflate in less than 1/25 of a second at speeds of up to 200 mi per hour (322 km per hour). Children are particularly vulnerable to head and neck trauma induced by air-bag deployment because their head-to-torso ratio is greater than that of adults and because their relatively flat occipital condyles, shallow joint surfaces, and poorly developed cervical musculature make the structural integrity of the neck much more dependent on intact ligaments. Neck injury is caused by ligamentous damage from severe hyperextension. To prevent this injury, children younger than 12 years of age should be properly restrained in the back seat.
Carlos A. Angel, M.D.
Richard A. Ehlers, M.D.
University of Texas Medical Branch, Galveston, TX 77555-0353
