Tony-winning actress Natasha Richardson died of a brain injury after falling on a ski slope, an autopsy found Thursday. The cause of death was an epidural hematoma (EDH).

EDH is a traumatic accumulation of blood between the inner table of the skull and the stripped-off dural membrane. The inciting event often is a focused blow to the head. The vast majority of these patients will have an overlying skull fracture as well. Blood vessels in close proximity to the fracture are the sources of the hemorrhage in the formation of an EDH. Because the underlying brain has usually been minimally injured, prognosis is excellent if treated aggressively. Outcome from surgical decompression and repair is related directly to patient's preoperative neurologic condition.

Fewer than 20% of patients demonstrate the classic presentation of a “lucid interval” between the initial trauma and subsequent neurological deterioration. Apparently, Ms. Richardson had this clinical course, as by all accounts she was neurologically intact for several hours following the traumatic insult.

The CT (CAT scan) image above is not of Ms. Richardson, but simply to illustrate the appearance of an EDH. It has a classic biconvex (ie, lens-like) shape, the red asterisk overlying the area of hemorrhage.