cauda equina       
noun [ C ]  anatomy specialized uk/ˌkɔː.də ekˈwaɪ.nə/ us/ˌkɑː.də ɪkˈwaɪ.nə/  caudae equinae /ˌkɔː.diː ekˈwaɪ.niː/ /ˌkɑː.diː ɪkˈwaɪ.niː/
 马尾(脊椎下部下降的脊髓神经束,形似马尾)
a group of nerves shaped like a horse's tail at the end of the spinal cord
  cauda equina syndrome 马尾综合症