Wiktionary
n. (context anatomy English) A bundle of nerve roots at the base of the spinal column
Wikipedia
The cauda equina (Latin for "horse's tail") is a bundle of spinal nerves and spinal nerve roots, consisting of the second through fifth lumbar nerve pairs, the first through fifth sacral nerve pairs, and the coccygeal nerve, all of which arise from the lumbar enlargement and the conus medullaris of the spinal cord. The cauda equina occupies the lumbar cistern, a subarachnoid space inferior to the conus medullaris. The nerves that compose the cauda equina innervate the pelvic organs and lower limbs to include motor innervation of the hips, knees, ankles, feet, internal anal sphincter and external anal sphincter. In addition, the cauda equina extends to sensory innervation of the perineum and, partially, parasympathetic innervation of the bladder.
Usage examples of "cauda equina".
And to think it all started with a single material: the neuronal membrane of the cauda equina, the divergent sheaf of spinal ganglia with the longest nerve roots of all.
And, indeed, the nerve mass is called cauda equina (kaw'duh ee-kw/nuh.
Horsetail was formerly official under the name of Cauda equina and was much esteemed as an astringent.