Final answer:
A spinal tap, or lumbar puncture, is performed in the lower lumbar area of the vertebral column to avoid damage to the spinal cord.
Step-by-step explanation:
A spinal tap, also known as a lumbar puncture, is performed in the lower lumbar area of the vertebral column to prevent damage to the spinal cord. The spinal cord does not extend through the lower lumbar region, so inserting a needle through the dura and arachnoid layers to withdraw cerebrospinal fluid (CSF) avoids the risk of damaging the central tissue of the spinal cord. This procedure is done to diagnose conditions such as meningitis and can also be used to deliver medications directly into the CSF.