## **Core Concept**
The spinal cord receives its blood supply from a network of arteries that arise from the aorta and other major arteries. The primary blood supply to the spinal cord comes from three main longitudinal arteries: the anterior spinal artery and two posterior spinal arteries. These arteries are supplemented by segmental arteries that arise from the aorta and other nearby arteries.

## **Why the Correct Answer is Right**
The correct answer, **D. Anterior spinal artery, posterior spinal arteries, and segmental arteries (or radiculomedullary and radiculopial arteries)**, is accurate because it encompasses the comprehensive blood supply to the spinal cord.
- The **anterior spinal artery** supplies the anterior two-thirds of the spinal cord.
- The **posterior spinal arteries** supply the posterior one-third of the spinal cord.
- The **segmental arteries**, including radiculomedullary and radiculopial arteries, contribute to the spinal cord's blood supply by anastomosing with the longitudinal spinal arteries, especially important at watershed areas.

## **Why Each Wrong Option is Incorrect**
- **Option A:** This option is incorrect because it only mentions the anterior spinal artery, omitting the significant contributions of the posterior spinal arteries and segmental arteries.
- **Option B:** This option is incorrect as it only lists the posterior spinal arteries and segmental arteries, neglecting the crucial role of the anterior spinal artery.
- **Option C:** This option might seem partially correct but is likely incorrect or incomplete because it does not explicitly mention the segmental arteries or clearly define the comprehensive network involved.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that the blood supply to the spinal cord can be segmental and watershed areas are particularly vulnerable to ischemia. The **arteria radiculomedullary** and **arteria radiculopial** play critical roles in reinforcing the blood supply to the spinal cord through their anastomoses with the longitudinal arteries.

## **Correct Answer:** D. Anterior spinal artery, posterior spinal arteries, and segmental arteries.