What is the term used for the collection of nerve roots at the end of the spinal cord?

The term used for the collection of nerve roots at the end of the spinal cord is the cauda equina. This structure resembles a horse's tail, which is reflected in its name; "cauda" means tail in Latin, and "equina" refers to horse. The cauda equina consists of a bundle of spinal nerves and spinal nerve rootlets that extend inferiorly from the conus medullaris, where the spinal cord tapers off at approximately the L1-L2 vertebral level.

This configuration is important because, as the spinal cord terminates, these nerve roots continue to descend through the vertebral canal before exiting the spinal column to innervate the lower limbs and pelvic organs, providing motor and sensory functions.

The other options refer to different anatomical structures either located within or associated with the central nervous system. The spinal bulb, more commonly known as the medulla oblongata, is part of the brainstem and is responsible for autonomic functions. The medulla oblongata and the cauda equina are not related to the collection of nerve roots at the end of the spinal cord. A nerve plexus refers to a network of intersecting nerves, typically found in the peripheral nervous system, such