What exactly is a subdural hematoma?

Bleed next to brain: Subdural hematoma is bleeding between the inner and middle layers of the tissues wrapping the brain. It can be secondary to trauma or occur spontaneously, especially in patients with significant brain atrophy. Depending on size and rate of growth they can often be managed conservatively, but sometimes require neurosurgical drainage.

Blod clot: Blod clot or collection under the dura on the surface of the brain.

SDH: A subdural hematoma typically occurs from bridging cortical veins being torn causing blood to accumulate on the surface of the brain under the dural covering of the brain. Trauma is the most common cause. In the elderly, even relatively minor head trauma can cause a sdh. Surgery is often used to evacuate the hematoma.