Editing Danger triangle of the face

{{Short description|Area of the face with blood supply that connects indirectly to the brain}}

{{for|the safety concept|Accident triangle}}
{{for|the safety equipment|Warning triangle}}

{{Use dmy dates|date=June 2021}}
{{Infobox anatomy
| Name        = Danger triangle of the face (Nasolabial triangle)
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| Image       = Danger triangle of the face diagram.jpg
| Caption     = The danger triangle of the area from the corners of the [[Human mouth|mouth]] to the bridge of the [[human nose|nose]]
| Width       = 250 px
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| Caption2    =
| Precursor   =
| System      =
| Artery      =
| Vein        =
| Nerve       =
| Lymph       =
}}

The '''danger triangle of the face''' consists of the area from the corners of the [[Human mouth|mouth]] to the bridge of the [[human nose|nose]], including the nose and [[maxilla]].<ref>{{cite journal|last=Hom|first=Milton M.|author2=Bielory, Leonard|title=The anatomical and functional relationship between allergic conjunctivitis and allergic rhinitis|journal=Allergy & Rhinology|date=1 January 2013|volume=4|issue=3|pages=110–119|doi=10.2500/ar.2013.4.0067|pmid=24498515|pmc=3911799}}</ref><ref name="Hollinshead">{{cite book | title=Anatomy for Surgeons: Volume 1 The Head and Neck | publisher=Harper & Row | author=Hollinshead WH | year=1968 | location=New York | isbn=9780061412646}}</ref> {{rp|pages=345–346}} Due to the special nature of the [[blood]] supply to the [[human nose]] and surrounding area, it is possible for retrograde infection from the nasal area to spread to the [[human brain|brain]], causing [[cavernous sinus thrombosis]], [[meningitis]], or [[brain abscess]].

This is possible because of veinous communication (via the [[ophthalmic vein]]s) between the [[facial vein]] and the [[cavernous sinus]]. The cavernous sinus lies within the [[cranial cavity]], between layers of the [[meninges]], and is a major conduit of venous drainage from the brain.<ref name="Osborn">{{cite journal | title=Craniofacial Venous Plexuses: Angiographic Study | author=Osborn AG | journal=American Journal of Roentgenology |date=Jan 1981  | volume=136 | issue=1 | pages=139–143 | doi=10.2214/ajr.136.1.139| pmid=6779561 | doi-access= }}</ref> Despite this relatively plausible anatomical argument, only severe facial infections (e.g., nasal abscess) can lead to a deeper central nervous system infection complication.

It was discovered that venous valves are present in the ophthalmic and facial veins. Thus, it is not the absence of venous valves but rather the existence of communications between the facial vein and cavernous sinus and the direction of blood flow that is important in the spread of infection from the face. Most people, but not all, have valves in these particular veins of the face.<ref>{{cite journal | pmid = 20491800 | doi=10.1111/j.1442-9071.2010.02325.x | volume=38 | issue=5 | title=Ophthalmic and facial veins are not valveless |date=July 2010 |vauthors=Zhang J, Stringer MD | journal=Clinical & Experimental Ophthalmology | pages=502–510| doi-access=free }}</ref>

The relationship between this area and a risk of cavernous sinus [[thrombosis]] was described as early as 1852.<ref name="Ludlow">{{cite journal | title=On carbuncular inflammation of lips and other parts of face. | author=Ludlow H | journal=Med. Times |date=Oct 1852  | volume=5 | pages=287–290}}</ref> In 1937, a study found that 61% of the cases of cavernous sinus thrombosis were the result of [[Boil|boil]]s on the upper part of the face.<ref name="Maes">{{cite journal | title=Infections of the Dangerous Areas of the Face | author=Maes U | journal=Annals of Surgery |date=July 1937  | volume=106 | issue=1 | pages=1–10 | pmc=1390530 | pmid=17857007 | doi=10.1097/00000658-193707000-00002}}</ref> While the disorder has become extremely uncommon with the development of antibiotics, it still carries a very small chance to develop a high [[mortality rate|risk of death]], and needs to be treated aggressively with [[antibiotics]] and [[anticoagulants|blood thinners]].<ref name="Okamoto">{{cite journal | title=Cavernous sinus thrombophlebitis related to dental infection{{snd}}two case reports. |vauthors=Okamoto H, Ogata A, Kosugi M, Takashima H, Sakata S, Matsushima T | journal=Neurologia Medico-Chirurgica | year=2012 | volume=52 | issue=10 | pages=757–760 | doi=10.2176/nmc.52.757|pmid=23095272 | doi-access=free }}</ref><ref name="Bhatia">{{cite journal | title=Septic cavernous sinus thrombosis secondary to sinusitis: are anticoagulants indicated? A review of the literature |vauthors=Bhatia K, Jones NS | journal=The Journal of Laryngology & Otology |date=Sep 2002  | volume=116 | issue=9 | pages=667–676 | doi=10.1258/002221502760237920 | pmid=12437798}}</ref>

== Infection of cavernous sinus ==
{{see also|Cavernous sinus thrombosis}}
If the [[cavernous sinus]] is infected, it can cause the blood within the sinus to [[coagulation|clot]], resulting in a [[cavernous sinus thrombosis]]. This affects the structures that are going through it or surround it. Inside the cavernous sinus, constriction of the following cranial nerves (CN) can be found: CN III ([[oculomotor nerve]]), CN IV ([[trochlear nerve]]), CN VI ([[abducens nerve]]), CN V ([[trigeminal nerve]]), specifically V1 ([[ophthalmic nerve]]) and V2 ([[maxillary nerve]]) branches. Failure of each of the nerves listed above will manifest in loss of function of the specific muscle, gland, or parasympathetic innervations (from CN III). In addition, it is possible that inflammation of the cavernous sinus will result in compression of the [[optic chiasm]] (resulting in vision problems) and/or the [[pituitary gland]].{{citation needed|date=August 2012}}

Failure of CN III will result in loss of function of the following muscles: [[medial rectus]], [[superior rectus]], [[inferior rectus]], and [[inferior oblique]], as well as muscles that are responsible for opening the eyelid: the [[levator palpebrae superioris muscle]] and the [[superior tarsal muscle]] (Müller's muscle). CN III damage also results in loss of parasympathetic innervation of the eye (loss of pupillary constriction and lens accommodation).{{citation needed|date=August 2012}}

== References ==
{{Reflist}}

==External links==
*{{cite web |url=http://www.nhs.uk/conditions/Cavernous-sinus-thrombosis/Pages/Introduction.aspx?url=Pages/what-is-it.aspx |title=Cavernous sinus thrombosis: Introduction |publisher=[[National Health Service]] |date=2006-02-10 |access-date=1 January 2009 |archive-date=3 March 2016 |archive-url=https://web.archive.org/web/20160303184440/http://www.nhs.uk/conditions/Cavernous-sinus-thrombosis/Pages/Introduction.aspx?url=Pages/what-is-it.aspx |url-status=dead }}
*{{cite web |url=http://www.drpaulose.com/ear/ent-pediatric-children/nasal-abscess-in-danger-area-of-face|title= Nasal Abscess in Danger Area of Face |date= 18 June 2010 |access-date=2011-04-08}}

[[Category:Human head and neck]]
[[Category:Face]]