Editing Nosebleed (section)

== Pathophysiology ==
[[File:Arteries of the Nose.jpg|alt=|thumb|upright=1.5|The arteries that supply Kiesselbach's plexus (responsible for anterior nosebleeds)]]
The nasal [[Mucous membrane|mucosa]] contains a rich blood supply that can be easily ruptured and cause bleeding. Rupture may be spontaneous or initiated by trauma. Nosebleeds are reported in up to 60% of the population with peak incidences in those under the age of ten and over the age of 50 and appear to occur in males more than females.<ref name="AAFP">{{cite journal |url=http://www.aafp.org/afp/20050115/305.html |title=Management of Epistaxis |journal=American Family Physician |volume=71 |issue=2 |pages=305–311 |author1=Corry J. Kucik |author2=Timothy Clenney |date=January 15, 2005 |access-date=January 31, 2010 |publisher=[[American Academy of Family Physicians]] |pmid=15686301 |archive-date=August 29, 2008 |archive-url=https://web.archive.org/web/20080829203041/http://www.aafp.org/afp/20050115/305.html |url-status=dead }}</ref> An increase in blood pressure (e.g. due to general hypertension) tends to increase the duration of spontaneous epistaxis.<ref>{{cite journal |doi=10.1097/00005537-199907000-00019 |author1=J. F. Lubianca Neto |author2=F. D. Fuchs |author3=S. R. Facco |author4=M. Gus |author5=L. Fasolo |author6=R. Mafessoni |author7=A. L. Gleissner |title=Is epistaxis evidence of end-organ damage in patients with hypertension? |journal=Laryngoscope |year=1999 |volume=109 |issue=7 |pages=1111–1115 |pmid=10401851|s2cid=22724992 }}</ref> [[Anticoagulant]] medication and disorders of blood clotting can promote and prolong bleeding. Spontaneous epistaxis is more common in the elderly as the nasal mucosa (lining) becomes dry and thin and blood pressure tends to be higher. The elderly are also more prone to prolonged nosebleeds as their blood vessels are less able to constrict and control the bleeding.

The vast majority of nosebleeds occur in the front [[anterior]] (front) part of the nose from the [[nasal septum]]. This area is richly endowed with blood vessels ([[Kiesselbach's plexus]]). This region is also known as [[Little's area]]. Bleeding farther back in the nose is known as a posterior bleed and is usually due to bleeding from [[Woodruff's plexus]], a venous plexus situated in the posterior part of inferior meatus.<ref>
The Journal of Laryngology & Otology (2008), 122: 1074–1077</ref> Posterior bleeds are often prolonged and difficult to control. They can be associated with bleeding from both nostrils and with a greater flow of blood into the mouth.<ref name="AAFP" />

{{Anchor|Pseudoepistaxis}} Sometimes blood flowing from other sources of bleeding passes through the nasal cavity and exits the nostrils. It is thus blood coming from the nose but is not a true nosebleed, that is, not truly originating from the nasal cavity. Such bleeding is called "pseudoepistaxis" (''[[wikt:pseudo-#Prefix|pseudo]]'' + ''epistaxis''). Examples include [[hemoptysis|blood coughed up]] through the [[airway]] and ending up in the nasal cavity, then dripping out.