Though some physicians may prefer to use the Trendelenberg position during injection, most do not. This is because the facial skin and muscles lie differently in this position, and therefore injecting based on the way the face looks in this position can leave results that weren't tailored to the way the face normally looks. I prefer to have patients slightly reclined with their legs up and lots of adequate lighting. The exact angle of the lighting can help me not only make out facial shadows and structures, but sometimes to see vasculature. The fact of the matter is, there are hundreds of vessels big and small in the face, and avoiding them is not always possible. Nicking a vessel and causing a bruise happens despite any and all precautions and anatomical knowledge because everyones anatomy is different.