Part of the arm (5)
I believe the answer is:
elbow
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">part of the arm</span>' is the definition.<br/ ><span class="explanation-format__explanation">('elbow' is part of 'arm')</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for elbow that I've seen before include "push" , "Below (anag.)" , "Major arm joint" , "Nudging joint?" , "part of the body" .)