Editing Bell's palsy (section)

==Signs and symptoms==
Bell's palsy is characterized by a one-sided facial droop that comes on within 72 hours.<ref name=CPG2013/> In rare cases (<1%), it can occur on both sides resulting in total facial paralysis.<ref>{{cite journal | vauthors = Price T, Fife DG | title = Bilateral simultaneous facial nerve palsy | journal = The Journal of Laryngology and Otology | volume = 116 | issue = 1 | pages = 46–48 | date = January 2002 | pmid = 11860653 | doi = 10.1258/0022215021910113 | s2cid = 19276545 }}</ref><ref>{{cite journal | vauthors = Jain V, Deshmukh A, Gollomp S | title = Bilateral facial paralysis: case presentation and discussion of differential diagnosis | journal = Journal of General Internal Medicine | volume = 21 | issue = 7 | pages = C7–10 | date = July 2006 | pmid = 16808763 | pmc = 1924702 | doi = 10.1111/j.1525-1497.2006.00466.x }}</ref>

The facial nerve controls many functions, such as blinking and closing the [[eye]]s, [[smiling]], [[frowning]], [[lacrimation]], [[salivation]], flaring [[nostrils]] and raising [[eyebrow]]s. It also carries [[taste]] sensations from the anterior two thirds of the [[tongue]], through the [[chorda tympani|chorda tympani nerve]] (a branch of the facial nerve). Because of this, people with Bell's palsy may present with [[Ageusia|loss of taste sensation]] in the anterior two thirds of the tongue on the affected side.<ref name=":0">{{Cite book|title = Fundamentals of Neurology|url = https://archive.org/details/fundamentalsneur00mume|url-access = limited| vauthors = Mumenthaler M, Mattle H | publisher = Thieme|year = 2006|isbn = 978-3131364517|location = Germany|pages = [https://archive.org/details/fundamentalsneur00mume/page/n208 197] }}</ref>

The facial nerve innervates the [[stapedius muscle]] of the [[middle ear]] (through the [[nerve to the stapedius|tympanic branch]]), which reflexively dampens the conduction of loud sounds. Thus, Bell's Palsy may cause normal sounds to be perceived as very loud ([[hyperacusis]]), and [[dysacusis]] is possible but hardly ever clinically evident.<ref name=":0" /><ref name=moore>{{Cite book|url=https://books.google.com/books?id=-Le5bc5F0sYC|title=Clinically Oriented Anatomy| vauthors = Moore KL, Dalley AF, Agur AM |year=2013 |publisher=Lippincott Williams & Wilkins |isbn=978-1451119459 }}</ref>