Bleeding between the dura mater and the arachnoid mater is characteristic of which condition, often venous in origin after a head injury?

• A. Epidural hematoma
• B. Subarachnoid hemorrhage
• C. Intracerebral hemorrhage
• D. Subdural hematoma

Answer: (D)

Bleeding between the dura mater and the arachnoid mater is a subdural hematoma. It happens when the bridging veins that run from the brain toward the dura are torn during head trauma. Because venous bleeding is slower, the bleed often accumulates gradually, with symptoms that may appear hours to days after the injury. On imaging, this type of collection is crescent-shaped and can cross the sutures of the skull, staying beneath the dura. This distinguishes it from an epidural hematoma, which is arterial and forms a lens-shaped collection between the skull and dura, usually with a rapid course and a brief lucid interval. Subarachnoid hemorrhage, by contrast, involves blood in the subarachnoid space around the brain and often presents with a sudden severe headache, while an intracerebral hemorrhage is bleeding within the brain tissue itself.