Detectives limiting corruption on a vessel (7)
I believe the answer is:
carotid
'vessel' is the definition.
(carotid is a type of blood vessel)
'detectives limiting corruption on a' is the wordplay.
'detectives' becomes 'CID' (abbreviation for Criminal Investigation Department).
'limiting' means one lot of letters goes inside another.
'corruption' becomes 'rot' (rot can mean corruption or decay).
'on' says to put letters next to each other.
'rot' put after 'a' is 'arot'.
'cid' going around 'arot' is 'CAROTID'.
(Other definitions for carotid that I've seen before include "Major artery in neck" , "major arteries" , "Acid rot in major artery (7)" , "Relating to neck arteries" .)