Joint from an ungulate served up (5)
I believe the answer is:
ankle
'joint' is the definition.
(ankle is a kind of joint)
'an ungulate served up' is the wordplay.
'ungulate' becomes 'elk' (elk is a kind of ungulate).
'served up' says the letters should be written in reverse.
'elk' backwards is 'kle'.
'an'+'kle'='ANKLE'
'from' is the link.
(Other definitions for ankle that I've seen before include "Major foot joint" , "Low joint" , "Narrow part of leg" , "Major joint in lower limb" , "Foot-leg connector" .)