Ruwan kashin baya, wanda kuma aka sani da ruwan cerebrospinal (CSF), ruwa ne bayyananne, marar launi wanda ke yawo a cikin kwakwalwa da kashin baya, yana ba da tasirin kwantar da hankali da samar da abinci mai gina jiki ga tsarin juyayi. Har ila yau yana taimakawa wajen cire kayan datti daga tsarin juyayi na tsakiya.
