What is the typical appearance of a subdural hemorrhage on imaging?

A subdural hemorrhage typically presents as a concave crescent-shaped bleed on imaging, particularly on a non-contrast computed tomography (CT) scan of the head. This shape arises due to the location of the bleeding, which occurs between the dura mater and the brain tissue. As blood accumulates in this space, it spreads out, conforming to the shape of the brain and resulting in the characteristic crescent shape.

Subdural hematomas are often venous in origin, commonly resulting from the tearing of bridging veins, and they can appear in varying sizes depending on the amount of blood accumulated. Additionally, this type of hemorrhage can be distinguished from an epidural hematoma, which typically appears as a convex lens-shaped bleed due to its location outside the dura mater and the pressure of the skull.

The other options describe appearances that do not correspond to subdural hemorrhages. A linear strip of bleeding might suggest a different type of injury or bleeding, while no significant findings would not be consistent with the presence of a subdural hemorrhage, which would be identifiable on imaging.