Re: could yawning be a way of stretching the muscles in our head?

could be
your guess is logical and as good as any of mine
you may look up yawning with a google.com search, and one thing you get is an 
answer already posted here at madsci.
 http://www.madsci.org/posts/archives/aug97/867090165.Me.r.html

truth is.. no one really knows..

ken mitton, phd
assistant professor of biomecial sciences http://ken.mitton.com/labstartpage.html