They're associated with seats (7)
I believe the answer is:
members
'seats' is the definition.
The answer and definition can be both body parts as well as being plural nouns.
Perhaps they are linked in a way I don't understand?
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for members that I've seen before include "People belonging" , "Parliamentarians" , "Limbs" , "body..." , "structural beams?" .)