Internal decapitation is exactly as the name insinuates, meaning that the internal ligaments connecting the vertebrae to the skull are severed. The misnomer associated with the name is that the head remains attached the body.
What is it?
Also known as an atlanto-occipital dislocation, this is an injury in which the top cervical vertebrae slip out of place due to trauma. If the ligaments that hold the vertebrae in place are severed, the head becomes unstable and may move around more than it should. This can cause damage to the lower brain stem which controls many basic functions of the brain including breathing.
Dr. Michael Yaszemski from the Mayo Clinic told CBS news that medical experts refer to it as a fracture dislocation of the C1 and C2 vertebrae, or a traumatic anterolisthesis of C1 and C2.
"It was a forward slippage [of C1 on C2] due to trauma," Yaszemski said. "It's quite remarkable this spinal cord works at all. We often see these types of injuries on post mortem exam because the arms and legs get paralyzed and the nerve that makes the diaphragm work comes off the spine and the patient can't breathe."
The injury is often fatal and is three times more common in children than in adults, according to a 2015 study. Children have proportionately heavier heads than adults as well as softer ligaments connecting their bones together. Both of these elements increase the likelihood of this injuring happening to a child over an adult.
The exact fatality rate due to atlanto-occipital dislocations is not known. Many of the possible victims of this injury do not undergo autopsy to discover this as the actual cause of death. A 2005 study of atlanto-occipital injuries at a Philadelphia hospital found that, over a 17-year period, 16 children with the injury were seen at the hospital, and only five of those children (31 percent) survived.
The main initial treatment after injury requires stabilization of the head and neck. A 2015 review study noted that internal decapitation "is an essentially ligamentous injury and, as such, is unlikely to spontaneously heal well over time, even after prolonged external immobilization." Surgery is the main course of treatment with this type of injury. Surgeons use rods, wires, and/or screws to stabilize the head and neck and prevent injury to the spinal cord.