I was thinking we'll probably get more readership if we include nudity. We've already shown a naked hand. So in today's showcase... the elbow.
Pardon me while i get technical, but the elbow is the bit that connects the upper arm bit to the bit below that, you know, with the hand on it. It moves and hinges about, but can't make it to your mouth.
And just look at it here in it's nakedness. Marvellous isn't it. Teasing you with a side profile shot.
For reference, when elbows occur on legs, they're known as knees.