**Core Concept**
The question tests the understanding of the anatomy and blood supply of the spine, specifically the relationship between blood vessels and the spinal epidural space.

**Why the Correct Answer is Right**
The internal vertebral venous plexus is a network of veins located in the epidural space, surrounding the spinal cord and vertebrae. When this plexus is damaged, it can lead to the accumulation of blood or fluid in the epidural space, causing symptoms such as headache and backache. This condition is known as an epidural hematoma. The internal vertebral venous plexus is a key structure to consider in this scenario because it is located in the epidural space and is closely associated with the spinal cord and vertebrae.

**Why Each Wrong Option is Incorrect**
**Option A:** The vertebral artery is a major artery that supplies blood to the brain and is not typically associated with the epidural space. Damage to the vertebral artery would more likely cause symptoms related to the brain or neck, rather than the back and headache described in the scenario.

**Option B:** The vertebral vein is a smaller vein that drains blood from the vertebral column, but it is not typically associated with the epidural space. Damage to the vertebral vein would be less likely to cause an epidural hematoma.

**Option C:** The external vertebral venous plexus is a network of veins located outside the vertebral column, in the subcutaneous tissue. While it is a potential source of bleeding, it is less likely to cause an epidural hematoma than the internal vertebral venous plexus.

**Clinical Pearl / High-Yield Fact**
It's worth noting that the internal vertebral venous plexus is a common site for epidural hematomas, particularly in cases of trauma or spinal surgery. Recognizing the anatomy of this plexus is crucial for understanding the pathophysiology of epidural hematomas and for making accurate diagnoses.

**Correct Answer Line**
✓ Correct Answer: D. Internal vertebral venous plexus