What is the characteristic shape of an epidural hematoma on imaging studies?

An epidural hematoma is characterized by a lentiform shape (often described as "lens-shaped") on imaging studies, particularly on CT scans. This appearance arises because the hematoma forms between the skull and the dura mater, causing a biconvex mass that does not cross suture lines due to the dura being tightly adhered to the inner surface of the skull at these junctions.

The lentiform shape is a key distinguishing feature that helps differentiate epidural hematomas from other types of hematomas, like subdural hematomas, which typically present with a crescent shape as they are formed between the dura and the brain, and can cross suture lines due to their location and the wider space between the dura and the brain tissue. Understanding the specific shapes associated with different types of hematomas is crucial for accurate diagnosis and management in clinical practice.