Extradural haemorrhage

Extradural haemorrhage in the skull is usually due to trauma at the pterion (the thinnest part of the calvarium or skull vault on its lateral aspect more anteriorly), which causes tearing of the middle meningeal artery or of one of its divisions. Depressed and diastatic skull fractures (fractures along the line of sutures with their widening, seen in infants) may be associated with extradural haemorrhage. The typical appearance on CT is of a lentiform high attenuation area of blood clot localised due to the tethering of the dura at the sutures.