Horse's foot part (7)
I believe the answer is:
pastern
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">horse's foot part</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I know that pastern is part of horse\\u0027s foot)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for pastern that I've seen before include "'The knee of an horse' (Johnson)" , "Word Johnson misdefined" , "Part of horse's foot" , "Fetter-bone of horse" , "Wrongly-defined part of horse" .)