Final answer:
The spinal cord in most adults ends between the first and second lumbar vertebrae, at the L1-L2 level.
Step-by-step explanation:
In most adults, the spinal cord ends at the upper lumbar region, specifically between the first and second lumbar vertebrae, which is referred to as the L1-L2 level. During development, the spinal cord does not grow as much as the vertebral column, which leads to the formation of the cauda equina, a bundle of nerve roots that extends from the terminal end of the spinal cord. The intervertebral foramina allow the spinal nerves to pass through and correspond to the level from which they emerge. As a result, the sacral spinal cord is situated at the level of the upper lumbar vertebral bones, and the spinal nerves extend to reach the appropriate level of the vertebral column.