Epidural vs subdural hematoma
- Lesion
Epidural bleeds are arterial and fast, between skull and dura; subdural bleeds are venous and slower, under the dura.
What it is
Trauma can tear vessels in the layers covering the brain. An epidural hematoma usually comes from a torn middle meningeal artery under a temporal fracture and grows fast between bone and dura. A subdural hematoma comes from bridging veins between the cortex and the dural sinuses and collects more slowly under the dura; it is common in older adults, people who drink heavily and infants. Both compress the brain and can cause herniation.
Structure
- Acute subdural: soft dark clot over the convexity, easily lifted from the arachnoid.
- Healing subdural: lysis of clot after about a week, granulation tissue grows from the dura within two weeks, and fibrous membranes form over months.
- The outer membrane is thick and vascular, the inner thin; fragile new vessels cause repeated bleeding.
Step by step
- A blow fractures the temporal bone or the brain moves and stretches bridging veins.
- Blood collects: fast under arterial pressure (epidural) or slowly (subdural).
- The clot acts as a mass and raises intracranial pressure.
- Without drainage, the brain herniates; a subdural that survives organises into membranes.
Epidural vs subdural hematoma
| Feature | Epidural | Subdural |
|---|---|---|
| Vessel | Middle meningeal artery (arterial) | Bridging veins (venous) |
| Space | Between skull and dura | Between dura and arachnoid |
| Shape on CT | Biconvex, lens-shaped | Crescent along the hemisphere |
| Crosses sutures | No (dura is attached there) | Yes |
| Typical patient | Young adult with a temporal fracture | Older adult, heavy drinker, infant |
| Speed | Hours; lucid interval | Days to weeks; can be chronic |
Clinical notes
- Epidural hematoma is a neurosurgical emergency; prompt evacuation usually gives a good outcome.
- Chronic subdural hematoma in older adults can look like dementia, with confusion and gait change.
Test yourself
Think of the answer, then tap the question to see it.
Which vessel usually causes an epidural hematoma?
The middle meningeal artery, torn by a fracture of the squamous temporal bone.
Why does an epidural hematoma not cross suture lines?
The dura is firmly attached to the skull at the sutures, so the collection is limited to one bone.
Why are older adults at higher risk of subdural hematoma?
Brain atrophy stretches the bridging veins, which tear with minor trauma.
Elsewhere in DurgiPedia
Connections
Educational content on the mechanisms of disease; not a diagnostic or treatment guide and no substitute for a health professional's advice. No doses are given.
Sources: Epidural Hematoma (StatPearls (NCBI Bookshelf), 2026); Subdural Hematoma (StatPearls (NCBI Bookshelf), 2026).
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Representative model, for educational purposes only.