- Epidural hemoatomas (EDH) are almost always associated with preceding head trauma
- Most intracranial EDHs result from skull fractures and the associated disruption or laceration of the arteries that lie along the inner table of the calvaria between the skull and the dura.
- The most common site of EDH is the temporoparietal region, where the middle meningeal arteryis lacerated.
- Blood accumulates at the site of arterial injury, seldom crossing the cranial suture lines because of the tightly adherent periosteum at the suture margins.
- Another cause of EDH is disruption of the dural venous sinuses in the dura adjacent to a skull fracture. As many as 30% of EDHs are venous.
 Imaging Findings
- Typical appearance is a biconvex, elliptical, extra-axial fluid collections.
- Acute EDH may contain both a hyperattenuating clot and a swirling lucency (believed to represent a mixture of active bleeding and the serum remaining after previous clot formation).
- Subacute EDH becomes homogeneously hyperattenuating.
- Chronic EDH is at least partly hypoattenuating as the clot undergoes breakdown and resorption.
 See Also
- Subdural hematoma
- Subarachnoid hemorrhage
- Intracerebral parenchymal hemorrhage
- Intraventricular hemorrhage
 External Links
- Douglas K McDonald E-medicine radiology article.