Which structure encases and protects the spinal cord?

The spinal canal serves as the protective enclosure for the spinal cord, allowing it to remain safeguarded within the bony structures of the vertebrae. The spinal canal is formed by the vertebral foramina, which are openings in each vertebra where the spinal cord runs through. This configuration provides not only physical protection from external forces and injury but also creates a channel for the safe passage of spinal nerves as they extend from the spinal cord to the rest of the body.

In contrast, while the vertebral arch and vertebral body contribute to the overall structure and protection of the spinal column, they do not specifically encase the spinal cord in the same comprehensive manner as the spinal canal. The vertebral arch forms the back part of each vertebra, but the combination of the arch and the body primarily form the boundaries of the spinal canal rather than encapsulating the spinal cord itself. The intervertebral discs function as cushioning pads between the vertebrae and are essential for mobility and shock absorption, but they do not provide direct protection for the spinal cord. Thus, the spinal canal remains the primary structure responsible for encasing and safeguarding the spinal cord.