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 not likely) for infections to spread directly to the brain from a cut, scratch or a popped pimple.
The path this infection would take would be back up the wrong way of a vein (called the ophthalmic veins) that runs from an empty hollow in the middle of the head at the bottom of the skull called the cavernous sinus. The cavernous sinus lies partly inside the skull, under the layers of protection against infection. The cavernous sinus is a way a lot of blood flows away from the brain back down the neck.
Many people wrongly assume that the veins of the head do not contain one-way valves like other veins of the circulatory system. In fact, almost all people, but not all, 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.
References[change | change source]
- Zhang J, Stringer MD (July 2010). "Ophthalmic and facial veins are not valveless". Clin. Experiment. Ophthalmol. 38 (5): 502–10. doi:10.1111/j.1442-9071.2010.02325.x. PMID 20491800.