Finger joint (7)
I believe the answer is:
knuckle
'finger joint' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for knuckle that I've seen before include "Bone of the fist" , "Part of the finger" , "Pork joint from the knee downwards" , "Knob at finger joint" , "Joint (of veal or pork?)" .)