What is the name of the last segment of the spinal cord?

The last segment of the spinal cord is identified as the conus medullaris. It is the cone-shaped termination of the spinal cord, which is located near the first or second lumbar vertebra (L1-L2) in adults. This structure signifies the end of the spinal cord proper, with spinal nerves branching off below it to form the cauda equina.

Recognizing the conus medullaris is essential for understanding the overall anatomy and functioning of the spinal cord, particularly how it transitions into the peripheral nervous system. The filum terminale, while connected to the conus medullaris and serving as an anchoring structure, is actually a fibrous extension that continues beyond it. The cauda equina consists of these spinal nerves that extend from the endings of the spinal cord, resembling a "horse's tail," and the lumbar enlargement refers to a part of the spinal cord that is wider to accommodate nerves that innervate the lower limbs. Understanding these distinctions is crucial in the context of neuroanatomy.