Hangman's fracture

A Hangman's fracture is the colloquial name given to a fracture of the pedicles or pars of the axis (C2 vertebra).

The mechanism of the injury is forcible hyperextension of the head. Traditionally this would occur during judicial hanging, when the noose was placed below the condemned subject's chin. When the subject was dropped, the head would be forced into hyperextension by the full weight of the body, a sufficient force to cause the fracture.

In the modern world, this injury is still sometimes seen, due to sports injuries or road traffic accidents. In deliberate or suicidal hanging, asphyxia is much more likely to lead to death.

A common symptom is a constricted pupil on the ipsilateral side (side where damage has occurred).This is due to loss of sympathetic innervation to the eye.The Long Cilliary nerve (a Sympathetic nerve) normally causes pupil dilation in response to decreased illumination. See pupillary light reflex.