Don't worry, I'm not going to suddenly change the subject of the blog into one of gruesome surgery or something! If you believe the judges at most camera clubs, it's a mortal sin to have people (or animals) in your pictures but to cut off any part of their body with the edge of the frame.
In other words you either have a whole person or nothing at all. No having the top of their head missing and absent limbs are a definite no-no.
Well I'm here to tell you that that's not necessarily the case. You can chop people up as much as you like but you have to make sure it looks deliberate! It is an oft-used technique of documentary photography when the main subject of your photo is not a person, but you want to show somehow that there are people in the vicinity.
The people almost become a symbolic representation of their job, or activity. As in the photo above. The people here have no heads so we have no idea of what they look like, or whether they're men or women. It's not a portrait. But they are wearing all black clothes, have big black boots on and are holding big hooks. They have become their job while losing their individuality. So it's a photo of the job of buying fish at a fish market.
The trick here is to cut them up decisively. Don't cut the top inch of their hair off at the top of the frame. Or their left hand at the wrist. When you only chop off a little bit it looks like an accident. People will wonder whether you just didn't notice that it was missing. Whereas when you chop them off in the middle of the chest they assume that it's deliberate - after all nobody's that bad a photographer! Or at least if they are they wouldn't be showing the pictures to other people. :)
So when you're attempting to show a scene, and the fact that there are people involved, but you're not necessarily aiming for a portrait, chop your subjects off. The person who's been chopped then becomes a symbol for what they are doing and it's left to the viewer's imagination as to what they look like.