A 22-year-old man sustains a temporal bone fracture in a road traffic accident. He is initially alert, then loses consciousness over 2 hours with ipsilateral pupillary dilatation. CT shows a biconvex (lens-shaped) hyperdense lesion. What is the source of bleeding in this condition?

• A Middle meningeal artery ✓
• B Bridging cortical veins
• C Cortical arteries
• D Dural venous sinuses

Explanation

The classic lucid interval with ipsilateral fixed dilated pupil and biconvex (lentiform) hyperdense lesion on CT is diagnostic of epidural hematoma. The bleeding source is most commonly the middle meningeal artery, which grooves the squamous temporal bone and is torn by fracture. Bridging veins cause subdural hematoma (crescent-shaped). Cortical and sinus sources are less common causes of epidural hematoma (Bailey and Love, 27th ed.).

Reference: Bailey and Love's Short Practice of Surgery, 27th ed.

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Written and medically reviewed by the StethoPrep medical team.