Right <a href="https://en.wikipedia.org/wiki/Knee" class="extiw" title="w:Knee">knee</a>, seen from an angle between anteriorly and laterally.
Derived from <a rel="nofollow" class="external autonumber" href="https://www.pueblo.gsa.gov/cic_text/health/qa-knee/Knee.gif">[1]</a>. Originally from <a class="external text" href="https://en.wikipedia.org">en.wikipedia</a>; description page is/was <a class="external text" href="https://en.wikipedia.org/w/index.php?title=Image%3AKnee_diagram.png">here</a>.