A subdural hematoma is a blood clot around
the surface of the brain, and below the dura mater (tough convering
of the brain). When it is old (chronic, over 3 weeks) it can
often be removed with a small burr hole, but when fresh (acute, several
hours to several days), a craniotomy (opening of the skull) is often
In the accompanying MRI of the brain,
the subdural hematoma can be seen in white, compressing the brain,
and shifting it to the side opposite the hematoma.