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.
Inflammation of cavernous sinus[change | change source]
If the cavernous sinus gets infected it will swell and squeeze what is going through it and what surrounds it. The following nerves could be squeezed by this swelling: CN III (eye moving nerve), CN IV (eye crossing nerve), CN VI (side looking nerve), CN V (face sensing nerve), specifically V1 (eye sensing nerve) and V2 (upper jaw sensing nerve) branches. If these nerves are squeezed they could fail to work, meaning you couldn't move a specific muscle, or couldn't focus your eyes(from CN III). Also, swelling or inflammation of the cavernous sinus could result in compression of the optic chiasm (resulting in vision problems) or the pituitary gland in the very center of the brain.[source?]
Failure of CN III will make these eye muscles not work: medial rectus, superior rectus, inferior rectus. These let the eyes look around. Also muscles that are responsible for opening the eyelid: levator palpebrae superioris muscle and the superior tarsal muscle (Muller’s muscle) will not work. CN III damage also could cause the eye to not be able to adjust from darkness to bright light or from looking near to looking far.[source?]
References[change | change source]
- Zhang J, Stringer MD (July 2010). "Ophthalmic and facial veins are not valveless". Clin. Experiment. Ophthalmol. 38 (5): 502–10. . .
Other websites[change | change source]
- "Cavernous sinus thrombosis: Introduction". National Health Service. 2006-02-10. http://www.nhs.uk/conditions/Cavernous-sinus-thrombosis/Pages/Introduction.aspx?url=Pages/what-is-it.aspx.
- "Nasal Abscess in Danger Area of Face". http://www.drpaulose.com/ear/ent-pediatric-children/nasal-abscess-in-danger-area-of-face. Retrieved 2011-04-08.