"type I (dysplastic/congenital): translation is secondary to an abnormal vertebral arch"
"type II (isthmic): translation is secondary to a lesion involving the pars interarticularis"
"subtype a (lytic): secondary to stress fracture, in most cases attributed to repeated extension and/or twisting motions"
"subtype b (elongated pars): result of multiple injury/healing events leading to elongation of the pars"
"subtype c (acute pars fracture): secondary to a single event and is rare"
"type III (degenerative): result of chronic instability and intersegmental degenerative changes"
"type V (pathological): diffuse or local disease compromising the usual structural integrity that prevents slippage"
"type I (dysplastic/congenital): translation is secondary to an abnormal vertebral arch"
"type IV (post-traumatic): fracture in a region other than the pars leading to slippage"
"History and etymology"