Appendages like this broken by heartless mob (6)
I believe the answer is:
thumbs
'appendages' is the definition.
(thumb is a kind of appendage)
'like this broken by heartless mob' is the wordplay.
'like this' becomes 'thus' (I've seen this before).
'broken by' means one lot of letters goes inside another (inserted letters break into the word).
'heartless' says to hollow out the word (remove centre letters).
'mob' with its middle taken out is 'mb'.
'thus' going around 'mb' is 'THUMBS'.
(Other definitions for thumbs that I've seen before include "Short thick digits" , "Hitches a lift" , "To be all these is to be clumsy" , "reads intensively" , "Digits; requests (lift)" .)