Cauda equina
Cauda equina
Definition
The cauda equina of the spinal cord refers to a bundle of spinal nerves and nerve roots that originate from the lower end of the spinal cord, specifically from the conus medullaris, and extend downwards within the lumbar and sacral regions of the vertebral canal. This structure resembles a horse's tail, which is the origin of its name. The cauda equina includes the lumbar, sacral, and coccygeal nerve roots, which provide sensory and motor innervation to the lower extremities, pelvic organs, and perineum.
The cauda equina is a consequence of the relative inequality in the rates of growth of the medulla spinalis and vertebral column, the nerve roots, which in the early embryo passed transversely outward to reach their respective intervertebral foramina, become more and more oblique in direction from above downward, so that the lumbar and sacral nerves descend almost vertically to reach their points of exit.
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