Jefferson fracture

A Jefferson fracture is a bone fracture of the anterior and posterior arches of the C1 vertebra, though it may also appear as a three- or two-part fracture. The fracture may result from an axial load on the back of the head or hyperextension of the neck (e.g. caused by diving), causing a posterior break, and may be accompanied by a break in other parts of the cervical spine.

It is named after the British neurologist and neurosurgeon Sir Geoffrey Jefferson, who reported four cases of the fracture in 1920 in addition to reviewing cases that had been reported previously.