A muscle that turns either way (7)
I believe the answer is:
rotator
'a muscle that turns' is the definition.
(I've seen this before)
'either way' is the wordplay.
I cannot quite understand how this works, but
'either' could be 'or' (I've seen this in another clue) and 'or' is found within the answer.
'way' could be 'r' (abbreviation for right) and 'r' is found within the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for rotator that I've seen before include "Something turning" , "Revolver" , "One goes around" , "anatomical drawing may reveal such muscle" , "Muscle that turns" .)