Sternum broken in German city (7)
I believe the answer is:
munster
'german city' is the definition.
(I've seen this in another clue)
'sternum broken' is the wordplay.
'broken' is an anagram indicator.
'sternum' is an anagram of 'MUNSTER'.
'in' acts as a link.
(Other definitions for munster that I've seen before include "Turns me into a province" , "Irish quarter?" , "European city" , "Irish province or German city" , "Province of Ireland" .)