Final answer:
The claim that there is no possibility of damaging the spinal cord below the third lumbar vertebra is false because the cauda equina, a bundle of nerve roots, exists at this level and can be damaged.
Step-by-step explanation:
The spinal cord is protected by the vertebrae and does not extend throughout the entire length of the vertebral column, terminating above the lower lumbar vertebrae. This allows for procedures such as lumbar punctures to take place without the risk of damaging the central tissue of the spinal cord, especially since below the third lumbar vertebra, the spinal cord has already given rise to the cauda equina, a bundle of nerve roots.
Therefore, even though the risk decreases significantly lower in the vertebral column, citing a total absence of any risk would be incorrect.
False: There is still a possibility of damaging the nerves of the cauda equina below the third lumbar vertebra, though it is diminished when compared to the risk of damaging the actual spinal cord tissue higher up.