An epidural hematoma is most accurately defined as:

• A. A collection of blood between the dura mater and the arachnoid mater
• B. A collection of blood between the arachnoid mater and the pia mater
• C. A collection of blood within the brain tissue itself
• D. A collection of blood between the dura mater and the skull

Answer: (D)

Verified step by step guidance

1. Step 1: Begin by understanding the anatomy of the meninges, which are the protective layers surrounding the brain and spinal cord. The three layers are the dura mater (outermost), arachnoid mater (middle), and pia mater (innermost).
2. Step 2: Recognize that an epidural hematoma refers to bleeding that occurs between the dura mater and the skull. This is distinct from other types of hematomas, such as subdural hematomas (between the dura mater and arachnoid mater) or intracerebral hematomas (within brain tissue).
3. Step 3: Analyze the options provided in the question. Eliminate choices that do not match the definition of an epidural hematoma. For example, bleeding between the arachnoid mater and pia mater describes a subarachnoid hemorrhage, not an epidural hematoma.
4. Step 4: Focus on the correct answer, which specifies the location of the blood collection as between the dura mater and the skull. This matches the definition of an epidural hematoma.
5. Step 5: Reinforce your understanding by noting that epidural hematomas are often caused by trauma, such as a skull fracture, which can rupture arteries (e.g., the middle meningeal artery) and lead to rapid accumulation of blood in this space.