Power Clean: Muscles Worked

I have been incorporating Power Cleans in my workout routine once a week. I separate the workout days by body parts.

I would like to know what specific body parts the Power Clean targets. Preferably, I'd like to know what the main muscle worked is (ex. lats, middle back, lower back) and what any other muscles are worked in this exercise.

[url]http://www.exrx.net/WeightExercises/OlympicLifts/Clean.html[/url]

I do my power cleans on shoulder day.

Main muscles used (which constitutes probably well over half the muscles in your body)
Quads
Hams
Glutes
Lower back
Middle back (i.e. traps)

The movement is essentially a pulling movement done in an explosive manner. It is not a shoulder/upper body movement. If it feels like one you are probably doing them wrong.