First, I thought I'd explain just what a Jefferson Fracture is.
It is a 3 or 4 place fracture of the C1 vertebra. Simple as that!
Research I have done on this injury reveals that it is most usually suffered by males (of which I am not); it is usually a sports-related injury, occuring most often from diving and equestrian accidents.
You can easily visualize what happens, if you wish.
The C1 is different than all other vertebrae in that it is comprised of one solid ring of bone. The C1 acts as a washer of sorts between the skull and the C2 and rest of the spine. It is called the Atlas bone, for like the mythical figure of old, this Atlas holds the weight of the world (aka skull) upon its shoulders.
To say it is a pretty important part of the spine, I guess, would be an understatement. Its proximity to the skull base and cranial nerves means that movement of only millimeters can have a profound effect.
When a person lands with great velocity onto the very top of their head (as in diving into shallow water), the skull is pushed with great force unto the C1 ring. Something's gotta give! A Jefferson Fracture occurs when that C1 breaks in 3 or 4 places.
Our anatomy in this area is all held in place by ligaments, including the ever-important "Transverse Ligament." In a STABLE Jefferson Fracture, the burst fracture of the C1 springs apart, and the ligaments pull things right back into shape. This is still a serious situation, but the ligaments still being functional means that the fracture is stable and more conservative measures can be taken for treatment.
However, if the burst fractures go wide enough, this is indicative that the ligaments were all ruptured, broken ("ripped and torn" my neurosurgeon told me), stretched beyond compare and unable to pull the C1 back into position. In fact, radiologists are taught to recognize that a Jefferson fracture is unstable and the tranverse ligament is compromised by how far gapped the fractured sites are.
When this happens, an UNSTABLE Jefferson Fracture has occurred and the treatment for this is much more aggressive. Websites and doctors seem to vary a little bit about the course of treatment, but the "minimal standard of care" seems to be traction in the hospital for a week or so, then a halo being installed for the patient to wear for 3 months or longer. The point of all of this is obviously: stability while things are healing. This stability is of utmost importance.
The C2 is also in the picture, as the odontoid (or dens, a part of the C2) sticks up into the off-center of the C1. The odontoid is something of a bony finger or tooth and makes the C2 a unique vertebra, as well. The transverse ligament travels between the C1 and C2.
Links are posted on this page to show further information on Jefferson Fractures, if you are further interested.