Kind of cord or column (6)
I believe the answer is:
spinal
This clue is a double definition.
'kind of cord' is the first definition.
(I've seen this in another clue)
'column' is the second definition.
(I've seen this before)
(Other definitions for spinal that I've seen before include "Type of column" , "sort of column" , "Plains (anag.)" , "affecting the back?" , "Member of dock family with edible stems" .)