Part of remark needs a bit of articulation (4)
I believe the answer is:
knee
'articulation' is the definition.
(I know that knee is a type of synovial joint)
'part of remark needs a bit' is the wordplay.
'part of' says the answer is hidden in the clue.
'KNEE' is hidden in the letters of 'remark needs bit'.
'of' is the link.
(Other definitions for knee that I've seen before include "joint input" , "middle part of leg" , "Major joint in leg" , "proposal might be made on one" , "Lower limb joint" .)