Most screenshots of keyhole lips are taken straight on. That's the angle that hides the part people actually disagree about.
The shape is a small parting in the middle with fullness on either side. Whether that fullness sits forward or stays flat changes the profile a lot, and clinic write-ups describe it both ways.
If you're saving reference photos, try to find one from the side as well. Then ask the injector which of the two profiles they'd aim for, and why.
My notes on the keyhole lip shape and where the sources split keep the demo faces and citations together. It's there to help you describe a look, not to plan a treatment.
Sofia R., LookPrep