Hospital within reach in poor quarter (6)
I believe the answer is:
ghetto
'poor quarter' is the definition.
(I've seen this before)
'hospital within reach' is the wordplay.
'hospital' becomes 'h'.
'within' is an insertion indicator.
'reach' becomes 'getto' (getting to is a kind of reaching**).
'h' placed inside 'getto' is 'GHETTO'.
'in' is the link.
(Other definitions for ghetto that I've seen before include "Restricted quarter" , "Part of city occupied by minority group, like old Jewish quarter" , "Ethic quarter" , "Historical Jewish quarter" , "A poor quarter of a city" .)