Danger triangle of the face

The danger triangle of the face is a triangle with two corners at both corners of the mouth and one corner in the middle of the nose between the eyes. The way the blood flows to the human nose is special, so it is possible (but very unlikely) for infections to spread directly to the brain from a cut, scratch or a popped pimple.
Almost all people have valves in the veins of the face. But even with one-way valves, blood flow between the facial vein and cavernous sinus can spread infection from the face. It is the direction of blood flow that is important. Infection may possibly lead to cavernous sinus thrombosis, meningitis or brain abscess.