Featured open-and-shut cases (7)
I believe the answer is:
eyelids
'featured open-and-shut cases' is the definition.
The definition and answer can be both body parts as well as being plural nouns.
Maybe they are linked in a way I don't understand?
This is all the clue.
Can you help me to learn more?
(Other definitions for eyelids that I've seen before include "They drop in sleep" , "covers for lamps" , "covers for lights?" .)