if u answer this,.
ok if u extend ur arms straight out and drop them at ur sides then keeping them straight bring ur arms dirctly in front of u do this movement ten times where are the muscles that cause this movemernt located?
Try here it may help:
http://vrlab.epfl.ch/~maurel/CHARM/WP3/Anatomy.html
or here ( I am not certain what you mean by straight out)..
http://www.bodybuilding.com/fun/exercises.php?MainMuscle=Shoulders