## Epidural Hematoma: Arterial Bleeding **Key Point:** Epidural hematoma (EDH) is a neurosurgical emergency caused by bleeding between the dura mater and the inner table of the skull. The most common source is laceration of the **middle meningeal artery (MMA)**, which runs in grooves along the inner surface of the temporal bone. ### Mechanism of Injury **High-Yield:** The middle meningeal artery is the dominant arterial supply to the dura and is vulnerable to laceration in temporal bone fractures — the most common site of EDH. The artery runs in a fixed groove, making it prone to tearing when the temporal bone is fractured by blunt trauma. ### Clinical Presentation & Imaging | Feature | Epidural Hematoma | | --- | --- | | **Location** | Between dura and skull (extradural) | | **Shape on CT** | Lens-shaped (biconvex), does not cross suture lines | | **Density** | Hyperdense (acute) | | **Bleeding source** | Arterial (high pressure) | | **Common site** | Temporal region (MMA injury) | | **Prognosis** | Good if evacuated early; poor if delayed | ### Why Middle Meningeal Artery? 1. **Anatomical vulnerability:** Runs in a groove along the inner table of the temporal bone. 2. **Temporal bone fractures:** Most common cause of EDH; MMA is injured in ~90% of cases. 3. **Arterial bleeding:** High-pressure source → rapid accumulation → mass effect and herniation if untreated. **Clinical Pearl:** The classic "talk and die" syndrome occurs when a patient has a lucid interval after initial loss of consciousness, then deteriorates rapidly due to expanding EDH. This is a neurosurgical emergency requiring immediate craniotomy. **Warning:** Do not confuse epidural hematoma (arterial, lens-shaped, does not cross sutures) with subdural hematoma (venous, crescent-shaped, crosses suture lines). [cite:Harrison 21e Ch 434]
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