There are two major classifications of brain bleeding, extra-axial -- meaning outside the brain proper -- and intra-axial -- meaning inside the brain tissue.

You probably didn't know that your little grey cells are covered with various membranes. The extra-axial bleeds are classified by where they are relative to these membranes.

* Epidural hematoma: between the skull and the (hard) dura mater

* Subdural hematoma: between the dura mater and the (weblike) arachnoid mater

* Subarachnoid hematoma: between the arachnoid mater and the (tender) pia mater

As one would expect, the epidural hematoma occurs closest to the skull and therefore is most likely to be caused by an external force. A recent example is the baseball pitcher Brandon McCarthy, who was hit in the head by a baseball and required surgery for epidural hematoma.

Subdural hematoma is often associated with extreme acceleration/deceleration of the head, as in a car accident or severe shaking. This type of brain bleed has perhaps the highest mortality rate.

Subarachnoid hemorrhage usually comes from inside the body rather than external trauma. The main underlying cause is usually found to be a malformation of the veins or arteries of the brain.

This is fascinating and also a little hard to follow, so let me see if I can tl;dr it:

There are two major types of brain bleeding (inside and outside), and one of them (outside the brain) has three subtypes that correspond roughly with being hit on the skull, extreme movement of the head, or something internal to the body.

Interestingly, it's extreme movement of the head that kills more often than being bonked on the head or something internal.

How'd I do?