Final answer:
A chronic subdural hematoma appears as a crescent-shaped collection of blood on a CT scan. It forms when blood vessels between the dura mater and arachnoid mater rupture and bleed.
Step-by-step explanation:
A chronic subdural hematoma appears as a crescent-shaped collection of blood on a CT scan. It forms when blood vessels between the dura mater and arachnoid mater rupture and bleed. The blood then accumulates gradually over time, causing pressure on the brain.
On a CT scan, a chronic subdural hematoma typically appears as a low-density area with a thin, well-defined border. It may have a concave shape and can be located between the brain surface and the dura mater.
It's important to note that the appearance of a chronic subdural hematoma on a CT scan can vary depending on the stage and size of the hematoma.