In all developed countries with up-to-date modern healthcare the primary treatment for mastoiditis is administration of  intravenous  antibiotics. Initially, broad-spectrum antibiotics are given, such as  ceftriaxone . As culture results become available, treatment can be switched to more specific antibiotics directed at the eradication of the recovered aerobic and  anaerobic bacteria . [ 8 ]  Long-term antibiotics may be necessary to completely eradicate the infection. [ 4 ]  If the condition does not quickly improve with antibiotics, surgical procedures may be performed (while continuing the medication). The most common procedure is a  myringotomy , a small incision in the  tympanic membrane  (eardrum), or the insertion of a  tympanostomy tube  into the eardrum. [ 9 ]  These serve to drain the pus from the middle ear, helping to treat the infection. The tube is extruded spontaneously after a few weeks to months, and the incision heals naturally. If there are complications, or the mastoiditis does not respond to the above treatments, it may be necessary to perform a  mastoidectomy : a procedure in which a portion of the bone is removed and the infection drained. [ 4 ]


With prompt treatment, it is possible to cure mastoiditis. Seeking medical care early is important. However, it is difficult for antibiotics to penetrate to the interior of the mastoid process and so it may not be easy to cure the infection; it also may recur. Mastoiditis has many possible complications, all connected to the infection spreading to surrounding structures.  Hearing loss  is likely, or inflammation of the  labyrinth  of the  inner ear  ( labyrinthitis ) may occur, producing  vertigo  and an ear ringing may develop along with the hearing loss, making it more difficult to communicate. The infection may also spread to the  facial nerve  (cranial nerve VII), causing  facial-nerve palsy , producing weakness or paralysis of some muscles of facial expression, on the same side of the face. Other complications include  Bezold's abscess , an abscess (a collection of pus surrounded by inflamed tissue) behind the  sternocleidomastoid muscle  in the neck, or a  subperiosteal abscess , between the periosteum and mastoid bone (resulting in the typical appearance of a protruding ear). Serious complications result if the infection spreads to the brain. These include  meningitis  (inflammation of the protective membranes surrounding the brain),  epidural abscess  (abscess between the skull and outer membrane of the brain), dural venous  thrombophlebitis  (inflammation of the  venous  structures of the brain), or  brain abscess . [ 2 ] [ 4 ]


In the United States and other developed countries, the  incidence  of mastoiditis is quite low, around 0.004%, although it is higher in developing countries.  The condition most commonly affects children aged from two to thirteen months, when ear infections most commonly occur. Males and females are equally affected. [ 3 ]


In  vertebrates , the  maxilla  ( pl. :  maxillae   / m æ k ˈ s ɪ l iː / ) [ 2 ]  is the upper fixed (not fixed in  Neopterygii )  bone  of the  jaw  formed from the fusion of two maxillary bones. In humans, the upper jaw includes the  hard palate  in the front of the  mouth . [ 3 ] [ 4 ]  The two maxillary bones are fused at the intermaxillary suture, forming the  anterior nasal spine . This is similar to the  mandible  (lower jaw), which is also a fusion of two mandibular bones at the  mandibular symphysis . The mandible is the movable part of the jaw.


The maxilla is a paired bone - the two maxillae unite with each other at the intermaxillary suture. The maxilla consists of: [ 5 ]


It has three surfaces: [ 5 ]


Features of the maxilla include: [ 5 ]


Each maxilla articulates with nine bones:  frontal ,  ethmoid ,  nasal ,  zygomatic ,  lacrimal , and  palatine  bones, the  vomer , the  inferior nasal concha , as well as the maxilla of the other side. [ 5 ]


Sometimes it articulates with the orbital surface, and sometimes with the  lateral pterygoid plate  of the  sphenoid .


The maxilla is ossified in membrane.  Mall  and Fawcett maintain that it is ossified from  two  centers only, one for the maxilla proper and one for the premaxilla. [ 6 ] [ 7 ]


These centers appear during the sixth week of  prenatal development  and unite in the beginning of the third month, but the suture between the two portions persists on the palate until nearly middle life. Mall states that the frontal process is developed from both centers.


The maxillary sinus appears as a shallow groove on the nasal surface of the bone about the fourth month of development, but does not reach its full size until after the second dentition.


The maxilla was formerly described as ossifying from six centers, viz.:


At birth the transverse and antero-posterior diameters of the bone are each greater than the vertical.


The frontal process is well-marked and the body of the bone consists of little more than the alveolar process, the teeth sockets reaching almost to the floor of the orbit.


The maxillary sinus presents the appearance of a furrow on the lateral wall of the nose. In the adult the vertical diameter is the greatest, owing to the development of the alveolar process and the increase in size of the sinus.


The  alveolar process  of the maxillae holds the upper teeth, and is referred to as the maxillary arch. Each maxilla attaches laterally to the  zygomatic bones  (cheek bones).


Each maxilla assists in forming the boundaries of three cavities:


Each maxilla also enters into the formation of two fossae: the  infratemporal  and  pterygopalatine , and two  fissures , the  inferior orbital  and  pterygomaxillary .
-When the tender bones of the upper jaw and lower nostril are severely or repetitively damaged, at any age the surrounding cartilage can begin to deteriorate just as it does after death. [ citation needed ]


A  maxilla fracture  is a form of  facial fracture . A maxilla fracture is often the result of  facial trauma  such as  violence ,  falls  or  automobile accidents . Maxilla fractures are classified according to the  Le Fort classification .


Sometimes (e.g. in bony fish), the maxilla is called "upper maxilla", with the mandible being the "lower maxilla". Conversely, in birds the upper jaw is often called "upper mandible".


In most vertebrates, the foremost part of the upper jaw, to which the  incisors  are attached in mammals consists of a separate pair of bones, the  premaxillae . These fuse with the maxilla proper to form the bone found in humans, and some other mammals. In  bony fish ,  amphibians , and  reptiles , both maxilla and premaxilla are relatively plate-like bones, forming only the sides of the upper jaw, and part of the face, with the premaxilla also forming the lower boundary of the  nostrils . However, in mammals, the bones have curved inward, creating the palatine process and thereby also forming part of the roof of the mouth. [ 8 ]


Birds  do not have a maxilla in the strict sense; the corresponding part of their  beaks  (mainly consisting of the premaxilla) is called "upper mandible".


Cartilaginous fish , such as sharks, also lack a true maxilla. Their upper jaw is instead formed from a  cartilaginous  bar that is not  homologous  with the bone found in other vertebrates. [ 8 ]


This article incorporates text in the  public domain  from  page 157  of the 20th edition of   Gray's Anatomy   (1918)


The  maxillary artery  (eg, internal maxillary artery) supplies deep structures of the face. It branches from the  external carotid artery  just deep to the neck of the mandible.


The maxillary artery, the larger of the two terminal branches of the  external carotid artery , arises behind the neck of the  mandible , and is at first imbedded in the substance of the  parotid gland ; it passes forward between the  ramus of the mandible  and the  sphenomandibular ligament , and then runs, either superficial or deep to the  lateral pterygoid muscle , to the  pterygopalatine fossa .


It supplies the deep structures of the face, and may be divided into  mandibular ,  pterygoid , and  pterygopalatine  portions.


The  first  or  mandibular   or  bony  portion passes horizontally forward, between the neck of the mandible and the sphenomandibular ligament, where it lies parallel to and a little below the  auriculotemporal nerve ; it crosses the  inferior alveolar nerve , and runs along the lower border of the  lateral pterygoid muscle .


Branches include:


The  second  or  pterygoid  or  muscular  portion runs obliquely forward and upward under cover of the ramus of the mandible and insertion of the  temporalis , on the superficial (very frequently on the deep) surface of the  lateral pterygoid muscle ; it then passes between the two heads of origin of this muscle and enters the fossa.


The  third  or  pterygopalatine [ 1 ]  or  pterygomaxillary portion  lies in the  pterygopalatine fossa  in relation with the  pterygopalatine ganglion .  This is considered the terminal branch of the maxillary artery.


This article incorporates text in the  public domain  from  page 559  of the 20th edition of   Gray's Anatomy   (1918)


The  maxillary hiatus  (also known as  maxillary sinus ostium ,  maxillary ostium , or  opening from the  maxillary sinus ) [ citation needed ]  is the opening of a  maxillary sinus  into the  middle nasal meatus  of the nasal cavity. It is situated superoposteriorly upon the lateral nasal wall, opening into the nasal cavity at the posterior portion of the  ethmoidal infundibulum . [ 1 ]  Its opening in the maxillary sinus is present upon the superior part of the medial wall of the sinus [ 2 ] [ 3 ]  near the roof of the  sinus ; [ 4 ]  because of the position, gravity cannot drain the maxillary sinus contents when the head is erect. [ 2 ] [ 3 ]


An accessory maxillary hiatus may be present either anterior or posterior to the inferior portion of the  uncinate process of ethmoid bone . [ 1 ]


It measures 2–4 mm in diameter [ 1 ]  with an average diameter of 2.4 mm. [ 2 ] [ 3 ]


It opens into the nasal cavity inferior to the  bulla ethmoidalis , and is partly obscured by the inferior end of the  uncinate process of ethmoid bone . [ 4 ]


The bone window of this aperture itself is much larger, but the actual opening is much reduced [ 3 ]  by the following: the uncinate process of the ethmoid superiorly, the  ethmoidal process of inferior nasal concha  inferiorly, the  perpendicular plate of palatine bone  posteriorly, and a small part of the lacrimal bone anteriorly and superiorly, [ 4 ]  as well as by the adjacent soft tissues. [ 3 ]


This article incorporates text in the  public domain  from  page 995  of the 20th edition of   Gray's Anatomy   (1918)


In  neuroanatomy , the  maxillary nerve  ( V 2 ) is one of the three branches or divisions of the  trigeminal nerve , the fifth (CN V)  cranial nerve .  It comprises the principal functions of  sensation  from the  maxilla ,  nasal cavity ,  sinuses , the  palate  and subsequently that of the mid-face, [ 1 ]  and is intermediate, both in position and size, between the  ophthalmic nerve  and the  mandibular nerve . [ 2 ]


It begins at the middle of the  trigeminal ganglion  as a flattened plexiform band then it passes through the lateral wall of the cavernous sinus. It leaves the skull through the  foramen rotundum , where it becomes more cylindrical in form, and firmer in texture. After leaving foramen rotundum it gives two branches to the pterygopalatine ganglion. It then crosses the  pterygopalatine fossa , inclines lateralward on the back of the  maxilla , and enters the orbit through the  inferior orbital fissure . It then runs forward on the floor of the orbit, at first in the infraorbital groove and then in the infraorbital canal remaining outside the periosteum of the orbit. It then emerges on the face through the  infraorbital foramen  and terminates by dividing into inferior palpebral, lateral nasal and superior labial branches. The nerve is accompanied by the infraorbital branch of (the third part of) the maxillary artery and the accompanying vein.


Its branches may be divided into four groups, depending upon where they branch off: in the cranium, in the pterygopalatine fossa, in the infraorbital canal, or on the face.


The Maxillary nerve gives cutaneous branches to the face. It also carries parasympathetic preganglionic fibers (sphenopalatine) and postganglionic fibers (zygomatic, greater and lesser palatine and nasopalatine) to and from the pterygopalatine ganglion.


This article incorporates text in the  public domain  from  page 889  of the 20th edition of   Gray's Anatomy   (1918)


The pyramid-shaped  maxillary sinus  (or antrum of  Highmore ) is the largest of the  paranasal sinuses , located in the  maxilla . It drains into the  middle meatus  of the nose [ 1 ] [ 2 ]  through the  semilunar hiatus . It is located to the side of the  nasal cavity , and below the orbit. [ 2 ]


It is the largest air sinus in the body. [ 1 ] [ 3 ]  It has a mean volume of about 10 ml. [ 1 ] [ verification needed ]  It is situated within the  body of the maxilla , [ 1 ] [ 3 ] [ 4 ]  but may extend into its  zygomatic  and  alveolar processes  when large. It is pyramid-shaped, with the apex at the maxillary  zygomatic process , and the base represented by the lateral nasal wall. [ 4 ]


It has three recesses: an alveolar recess pointed inferiorly, bounded by the  alveolar process  of the maxilla; a zygomatic recess pointed laterally, bounded by the  zygomatic bone ; and an infraorbital recess pointed superiorly, bounded by the inferior  orbital surface of the maxilla . The medial wall is composed primarily of  cartilage . [ 1 ] [ 3 ]


The nasal wall of the maxillary sinus, or base, presents, in the disarticulated bone, a large, irregular aperture that communicates with the  nasal cavity . [ citation needed ]  In the articulated skull this aperture is much reduced in size by the following bones:


The sinus communicates through an opening into the  semilunar hiatus  on the lateral nasal wall. [ citation needed ]


The medial wall is composed primarily of  cartilage . [ 1 ] [ 3 ]


On the posterior wall are the  alveolar canals , transmitting the  posterior superior alveolar vessels  and  nerves  to the  molar  teeth. [ citation needed ]


The floor is formed by the  alveolar process , and, if the sinus is of an average size, is on a level with the floor of the nose; if the sinus is large it reaches below this level. [ citation needed ]  Projecting into the floor of the antrum are several conical processes, corresponding to the roots of the first and second maxillary  molar teeth ; in some cases the floor can be perforated by the apices of the teeth. [ citation needed ]


The roof is formed by the floor of the orbit. It is traversed by infraorbital nerves and vessels. [ citation needed ]


The  infraorbital canal  forms a ridge at the junction of the roof and anterior wall of the sinus; [ 4 ]  additional ridges are sometimes seen in the posterior wall of the cavity and are caused by the  alveolar canals . [ citation needed ]


The mucous membranes receive their mucomotor  postganglionic   parasympathetic  nerve fibres from the  pterygopalatine ganglion . [ citation needed ]


The superior alveolar (anterior, middle, and posterior) nerves, branches of the  maxillary nerve  provide  sensory innervation . [ citation needed ]


The sinus is lined with  mucoperiosteum , with cilia that beat toward the ostia. This  membranous  lining is also referred to as the  Schneiderian membrane , which is  histologically  a bilaminar membrane with  pseudostratified ciliated columnar epithelial cells  on the internal (or cavernous) side and  periosteum  on the  osseous  side. The size of the sinuses varies in different  skulls , and even on the two sides of the same skull. [ 3 ]


The roof of the sinus is also the floor of the  orbit . Posterior to the sinus and its wall are the  pterygopalatine fossa  and the  infratemporal fossa . [ 4 ]


After puberty, the maxillary sinus rapidly increases in size. Its size is variable in the adult; if large, it may extend into the  zygomatic process  and  alveolar process  of the maxilla. [ 4 ]


Extension into the maxillary alveolar process may cause the roots of the molars and even premolars to lie just beneath the floor of the sinus or even project through the floor and into the sinus; in such cases, the roots of the teeth are typically surrounded by a thin layer of bone, but may sometimes lie directly underneath the mucous membrane of the sinus. Projection of the roots into the maxillary sinus is more common in advanced age due to  bone resorption . In such cases, tooth extraction can create a  fistula  between the  oral cavity  and the sinus that nevertheless usually resolves spontaneously. [ 4 ]


Maxillary sinus is the first  paranasal sinuses  to form. At birth, it is about 6 to 8 cm 3  in volume, elongated, as is orientated in antero-posterior direction, located at the next to the medial orbital wall of the eye. The lateral wall of the maxillary sinus goes beneath the medial orbital wall during the first year of life, extends laterally pass the  infraorbital groove  by the age of four years, and reach the  maxilla  by the age of nine years. [ 5 ]  After the first  permanent tooth  erupted at the age of six to seven, aeration of maxillary sinus is the main growth feature. [ 5 ] [ 6 ]  At the final phase of aeration, the floor of maxillary sinus is four to five milimetres below the floor of  nasal cavity . However, timing of maxillary sinus growth is variable in different people. [ 5 ]


Maxillary  sinusitis  is  inflammation  of the maxillary sinuses. The  symptoms  of sinusitis are headache, usually near the involved sinus, and foul-smelling nasal or pharyngeal discharge, possibly with some systemic signs of infection such as fever and weakness. The skin over the involved sinus can be tender, hot, and even reddened due to the inflammatory process in the area. On radiographs, there is opacification (or cloudiness) of the usually translucent sinus due to retained mucus. [ 7 ]


Maxillary sinusitis is common due to the close anatomic relation of the frontal sinus, anterior  ethmoidal sinus  and the maxillary teeth, allowing for easy spread of infection. Differential diagnosis of dental problems needs to be done due to the close proximity to the teeth since the pain from sinusitis can seem to be dentally related. [ 1 ]   Furthermore, the drainage orifice lies near the roof of the sinus, and so the maxillary sinus does not drain well, and infection develops more easily. The maxillary sinus may drain into the   mouth  via an abnormal opening, an oroantral  fistula , a particular risk after tooth extraction.


An OAC is an abnormal physical communication between the maxillary sinus and the mouth. This opening is only present when the structures that normally separates the mouth and sinus into 2 separate compartments are lost. [ 8 ]


There are many causes of an OAC. The most common reason is following extraction of a posterior maxillary (upper)  premolar  or  molar  tooth. Other causes include trauma, pathology (e.g. tumours or cysts), infection or iatrogenic damage during surgery. Iatrogenic damage during dental treatment accounts for nearly half of the incidence of dental-related maxillary sinusitis. [ 9 ]  There is always a thin layer of mucous membrane ( Schneiderian membrane ) and usually bone between the roots of the upper back teeth and the floor of the maxillary sinus. However, the bone can vary in thickness in different individuals, ranging from complete absence to 12mm thick. [ 9 ]  Therefore, in certain individuals the membrane +/- the bony floor of the sinus can be perforated easily, creating an opening into the mouth when a tooth is extracted. [ 10 ]


An OAC that is smaller than 2mm can heal spontaneously i.e. closure of the opening. [ 11 ]  Those that are larger than 2mm have a higher chance of developing into  oro-antral fistula (OAF) . [ 11 ]  The passage is only defined as an OAF if it is persistent and lined by  epithelium . [ 11 ]  Epithelialisation happens when an OAC persist for at least 2–3 days and oral epithelial cells proliferate to line the defect. Large defects (more than 2mm) should be surgically closed as soon as possible to avoid accumulation of food and saliva which could contaminate the maxillary sinus, leading to infection (sinusitis). [ 11 ]  Various surgical techniques can be employed to manage an OAF but the most common involves pulling and stitching some soft tissue from the gum to cover the opening (i.e. soft tissue flap). [ 11 ]


Traditionally the treatment of acute maxillary sinusitis is usually prescription of a broad-spectrum  cephalosporin  antibiotic resistant to beta-lactamase, administered for 10 days. Recent studies have found that the cause of chronic sinus infections lies in the nasal mucus, not in the nasal and sinus tissue targeted by standard treatment. This suggests a beneficial effect in treatments that target primarily the underlying and presumably damage-inflicting nasal and sinus membrane inflammation, instead of the secondary bacterial infection that has been the primary target of past treatments for the disease. Also, surgical procedures with chronic sinus infections are now changing with the direct removal of the mucus, which is loaded with toxins from the inflammatory cells [ citation needed ] , rather than the inflamed tissue during surgery. Leaving the mucus behind might predispose early recurrence of the chronic sinus infection. If any surgery is performed, it is to enlarge the ostia in the lateral walls of the nasal cavity, creating adequate drainage. [ 7 ]


Carcinoma  of the maxillary sinus may invade the palate and cause dental pain. It may also block the nasolacrimal duct. Spread of the tumor into the orbit causes  proptosis . [ 1 ]


With age, the enlarging maxillary sinus may even begin to surround the roots of the maxillary posterior teeth and extend its margins into the body of the zygomatic bone. If the maxillary posterior teeth are lost, the maxillary sinus may expand even more, thinning the bony floor of the alveolar process so that only a thin shell of bone is present. [ 7 ]


The maxillary sinus was first discovered and illustrated by  Leonardo da Vinci , but the earliest attribution of significance was given to  Nathaniel Highmore , the British surgeon and anatomist who described it in detail in his 1651 treatise. [ 12 ]


Ménière's disease  ( MD ) is a disease of the  inner ear  that is characterized by potentially severe and incapacitating episodes of  vertigo ,  tinnitus ,  hearing loss , and a feeling of fullness in the ear. [ 3 ] [ 4 ]  Typically, only one ear is affected initially, but over time, both ears may become involved. [ 3 ]  Episodes generally last from 20 minutes to a few hours. [ 5 ]  The time between episodes varies. [ 3 ]  The hearing loss and ringing in the ears can become constant over time. [ 4 ]


The cause of Ménière's disease is  unclear , but likely involves both genetic and environmental factors. [ 1 ] [ 3 ]  A number of theories exist for why it occurs, including constrictions in blood vessels, viral infections, and autoimmune reactions. [ 3 ]  About 10% of cases run in families. [ 4 ]  Symptoms are believed to occur as the result of increased fluid buildup in the  labyrinth  of the inner ear. [ 3 ]  Diagnosis is based on the symptoms and a  hearing test . [ 3 ]  Other conditions that may produce similar symptoms include  vestibular migraine  and  transient ischemic attack . [ 1 ]


No cure is known. [ 3 ]  Attacks are often treated with medications to help with the  nausea  and  anxiety . [ 4 ]  Measures to prevent attacks are overall poorly supported by the evidence. [ 4 ]  A low-salt diet,  diuretics , and  corticosteroids  may be tried. [ 4 ]   Physical therapy  may help with balance and  counselling  may help with anxiety. [ 3 ] [ 4 ]  Injections into the ear or surgery may also be tried if other measures are not effective, but are associated with risks. [ 3 ] [ 5 ]  The use of  tympanostomy tubes  (ventilation tubes) to improve vertigo and hearing in people with Ménière's disease is not supported by definitive evidence. [ 5 ]


Ménière's disease was identified in the early 1800s by  Prosper Menière . [ 5 ]  It affects between 0.3 and 1.9 per 1,000 people. [ 1 ]  The onset of Ménière's disease is usually around 40 to 60 years old. [ 3 ] [ 6 ]  Females are more commonly affected than males. [ 1 ]  After 5-15 years of symptoms, episodes that include dizziness or a sensation of spinning sometimes stop and the person is left with loss of balance, poor hearing in the affected ear, and ringing or other sounds in the affected ear or ears. [ 5 ]


Ménière's is characterized by recurrent episodes of vertigo, fluctuating hearing loss, and tinnitus; episodes may be preceded by a headache and a feeling of fullness in the ears. [ 4 ]  People may also experience additional symptoms related to irregular reactions of the  autonomic nervous system . These symptoms are not symptoms of Ménière's disease per se, but rather are side effects resulting from failure of the organ of hearing and balance, and include nausea,  vomiting , and  sweating , which are typically symptoms of vertigo, and not of Ménière's. [ 1 ]  This includes a sensation of being pushed sharply to the floor from behind. [ 5 ]  Sudden falls without loss of consciousness ( drop attacks ) may be experienced by some people. [ 1 ]


The cause of Ménière's disease is unclear, but likely involves both genetic and environmental factors. [ 1 ] [ 3 ] [ 7 ]  A number of theories exist including constrictions in blood vessels, viral infections, and autoimmune reactions. [ 3 ]


The initial triggers of Ménière's disease are not fully understood, with a variety of potential inflammatory causes that lead to  endolymphatic hydrops , a distension of the  endolymphatic  spaces in the inner ear.  Endolymphatic hydrops  (EH) is strongly associated with developing Ménière's disease, [ 1 ]  but not everyone with EH develops Ménière's disease: "The relationship between endolymphatic hydrops and Meniere's disease is not a simple, ideal correlation." [ 8 ]  Notably, mild EH can also occur in  vestibular migraine  which is an important differential diagnosis for Ménière's disease. [ 9 ]


Additionally, in fully developed Ménière's disease, the balance system ( vestibular system ) and the hearing system ( cochlea ) of the inner ear are affected, but some cases occur where EH affects only one of the two systems enough to cause symptoms. The corresponding subtypes of the disease are called vestibular Ménière's disease, showing symptoms of vertigo, and cochlear Ménière's disease, showing symptoms of hearing loss and tinnitus. [ 10 ] [ 11 ] [ 12 ] [ 13 ]


The mechanism of Ménière's disease is not fully explained by EH, but fully developed EH may mechanically and chemically interfere with the sensory cells for balance and hearing, which can lead to temporary dysfunction and even to death of the sensory cells, which in turn can cause the typical symptoms of MD – vertigo, hearing loss, and tinnitus. [ 8 ] [ 11 ]


An estimated 30% of people with Ménière's disease have  Eustachian tube dysfunction . [ 14 ]


The diagnostic criteria as of 2015 define definite MD and probable MD as: [ 1 ] [ 4 ]


Definite


Probable


A common and important symptom of MD is  hypersensitivity to sounds . [ 16 ]  This hypersensitivity is easily diagnosed by measuring the loudness discomfort levels (LDLs). [ 17 ]


Symptoms of MD overlap with  migraine-associated vertigo  (MAV) in many ways, but when hearing loss develops in MAV, it is usually in both ears, and this is rare in MD, and hearing loss generally does not progress in MAV as it does in MD. [ 1 ]


People who have had a  transient ischemic attack  (TIA) or  stroke  can present with symptoms similar to MD, and in people at risk  magnetic resonance imaging   should be conducted to exclude TIA or stroke. [ 1 ]


Other vestibular conditions that should be excluded include  vestibular paroxysmia ,  recurrent unilateral vestibulopathy ,  vestibular schwannoma , or a tumor of the  endolymphatic sac . [ 1 ]


No cure for Ménière's disease is known, but medications, diet, physical therapy, counseling, and some surgical approaches can be used to manage it. [ 4 ]  More than 85% of patients with Ménière's disease get better from changes in lifestyle, medical treatment, or minimally invasive surgical procedures. Those procedures include intratympanic steroid therapy, intratympanic gentamicin therapy or  endolymphatic sac surgery . [ 18 ]


During MD episodes,  medications to reduce nausea  are used, as are  drugs to reduce the anxiety  caused by vertigo. [ 4 ] [ 19 ]  For longer-term treatment to stop progression, the evidence base is weak for all treatments. [ 4 ]  Although a causal relation between allergy and Ménière's disease is uncertain,  medication to control allergies  may be helpful. [ 20 ]  To assist with vertigo and balance problems,  glycopyrrolate  has been found to be a useful vestibular suppressant in patients with Ménière's disease. [ 21 ]


Diuretics , such as the thiazide-like diuretic  chlortalidone , are widely used to manage MD on the theory that it reduces fluid buildup (pressure) in the ear. [ 22 ]  Based on evidence from multiple but small clinical trials, diuretics appear to be useful for reducing the frequency of episodes of dizziness but do not seem to prevent hearing loss. [ 23 ] [ 24 ]


In cases where hearing loss and continuing severe episodes of vertigo occur, a  chemical labyrinthectomy , in which a medication such as  gentamicin  is injected into the middle ear and kills parts of the vestibular apparatus, may be prescribed. [ 4 ] [ 25 ] [ 26 ]  This treatment has the risk of worsening hearing loss. [ 25 ]


People with MD are often advised to reduce their sodium intake. [ 19 ] [ 27 ]  Reducing salt intake, however, has not been well studied. [ 27 ]  Based on the assumption that MD is similar in nature to a migraine, some advise eliminating "migraine triggers" such as caffeine, but the evidence for this is weak. [ 19 ]  There is no high-quality evidence that changing diet by restricting salt, caffeine or alcohol improves symptoms. [ 28 ]


While use of physical therapy early after the onset of MD is probably not useful due to the fluctuating disease course, physical therapy to help retraining of the balance system appears to be useful to reduce both subjective and objective deficits in balance over the longer term. [ 4 ] [ 29 ]


The psychological distress caused by the vertigo and hearing loss may worsen the condition in some people. [ 30 ]  Counseling may be useful to manage the distress, [ 4 ]  as may education and  relaxation techniques . [ 31 ]


If symptoms do not improve with less invasive approaches and for cases where the condition is uncontrolled or persistent and affecting both ears, surgery may be considered. [ 4 ] [ 19 ] [ 32 ]


Surgery to decompress the  endolymphatic sac  is one surgical approach that is sometimes suggested. Three methods of surgical endolymphatic sac decompression are sometimes suggested – simple decompression, insertion of a shunt, or removal of the sac. [ 33 ]  There is some very weak evidence that all three methods may be useful for reducing dizziness, but that the level of evidence supporting these surgical procedures is low with further higher quality investigations being suggested. [ 33 ]  There is a risk in these types of surgical procedures that the shunts used in these surgeries are at risk of becoming displaced or misplaced. [ 19 ]  For those with severe cases who are eligible for endolymphatic sac decompression, a 2014 systematic review reported that in at least 75% of people, EL sac decompression was effective at controlling vertigo in the short term (>1 year of follow-up) and long term (>24 months). [ 34 ]


Surgical implantation of eustachian tubes (ventilation tubes) is not strongly supported by medical studies. There are some tentative evidence of benefit from  tympanostomy tubes  for improvement in the unsteadiness associated with the disease, [ 14 ]  conclusions about how effective this surgery is and the potential for side effects and harms is not clear. [ 5 ] [ 32 ]


Destructive surgeries such as vestibular nerve  labyrinthectomy  are irreversible and involve removing entire functionality of most, if not all, of the affected ear; as of 2013, almost no evidence existed with which to judge whether these surgeries are effective. [ 35 ]  The inner ear itself can be surgically removed via labyrinthectomy, although hearing is always completely lost in the affected ear with this operation. [ 35 ]  The surgeon can also cut the nerve to the balance portion of the inner ear in a  vestibular   neurectomy . The hearing is often mostly preserved; however, the surgery involves cutting open into the lining of the brain, and a hospital stay of a few days for monitoring is required. [ 35 ]


Ménière's disease usually starts confined to one ear; it extends to both ears in about 30% of cases. [ 5 ]  People may start out with only one symptom, but in Ménière's disease all three appear with time. [ 5 ]  Hearing loss usually fluctuates in the beginning stages and becomes more permanent in later stages. Ménière's disease has a course of 5–15 years, and people generally end up with mild disequilibrium, tinnitus, and moderate hearing loss in one ear. [ 5 ]
As of 2020, there has been no recent major breakthrough in the pathogenesis research of Ménière's disease. [ 45 ]


From 3 to 11% of diagnosed dizziness in neuro-otological clinics are due to Ménière's disease. [ 46 ]  The annual incidence rate is estimated to be about 15 cases per 100,000 people and the prevalence rate is about 218 per 100,000, and around 15% of people with Ménière's disease are older than 65. [ 46 ]  In around 9% of cases, a relative also had Ménière's disease, indicating a genetic predisposition in some cases. [ 4 ]


The odds of Ménière's disease are greater for people of white ethnicity, with severe obesity, and women. [ 1 ]  Several conditions are often comorbid with Ménière's disease, including  arthritis ,  psoriasis ,  gastroesophageal reflux disease ,  irritable bowel syndrome , and  migraine . [ 1 ]


The condition is named after the French physician  Prosper Menière , who in an 1861 article described the main symptoms and was the first to suggest a single disorder for all of the symptoms, in the combined organ of balance and hearing in the inner ear. [ 47 ] [ 48 ]


The  American Academy of Otolaryngology  – Head and Neck Surgery Committee on Hearing and Equilibrium set criteria for diagnosing MD, as well as defining two subcategories – cochlear (without vertigo) and vestibular (without deafness). [ 49 ]


In 1972, the academy defined criteria for diagnosing MD as: [ 49 ]


In 1985, this list changed to alter wording, such as changing "deafness" to "hearing loss associated with tinnitus, characteristically of low frequencies" and requiring more than one attack of vertigo to diagnose. [ 49 ]  Finally in 1995, the list was again altered to allow for degrees of the disease: [ 49 ]


In 2015, the International Classification for Vestibular Disorders Committee of the Barany Society published consensus diagnostic criteria in collaboration with the American Academy of Otolaryngology–Head and Neck Surgery, the European Academy of Otology and Neurootology, the Japan Society for Equilibrium Research, and the Korean Balance Society. [ 1 ] [ 4 ]


The  mental space  is a  fascial space of the head and neck  (also termed  fascial  spaces or tissue spaces). It is a  potential space , bilaterally located in the chin, between the  mentalis muscle   superiorly  and the  platysma muscle   inferiorly . These spaces may be created by  pathology , e.g., the spread of  odontogenic infection . Commonly the origin of the infection is an  anterior   mandibular  tooth with associated  periapical abscess  which erodes through the buccal cortical plate of the mandibular at a level below the attachment of the mentalis muscle. The mental space also has the mental foramen located laterally on both the right and left sides. This is important as many mandibular nerves pass through these foremens.  [ 1 ]


Microsurgery  is a general term for  surgery  requiring an  operating microscope . The most obvious developments have been procedures developed to allow  anastomosis  of successively smaller blood vessels and nerves (typically 1 mm in diameter) which have allowed transfer of tissue from one part of the body to another and re-attachment of severed parts. Microsurgical techniques are utilized by several specialties today, such as  general surgery ,  ophthalmology ,  orthopedic surgery ,  gynecological surgery ,  otolaryngology ,  neurosurgery ,  oral and maxillofacial surgery ,  endodontic microsurgery ,  plastic surgery ,  podiatric surgery   and  pediatric surgery .


Otolaryngologists were the first physicians to use microsurgical techniques. A Swedish  otolaryngologist , Carl-Olof Siggesson Nylén (1892–1978), was the father of microsurgery. In 1921, in the University of Stockholm, he built the first surgical microscope, a modified monocular Brinell-Leitz microscope. At first he used it for operations in animals. In November of the same year he used it to operate on a patient with chronic otitis who had a labyrinthine fistula. Nylen's microscope was soon replaced by a binocular microscope, developed in 1922 by his colleague Gunnar Holmgren (1875–1954). [ citation needed ]


Gradually the  operating microscope  began to be used for ear operations. In the 1950s many otologists began to use it in the  fenestration  operation, usually to perfect the opening of the  fenestra  in the lateral semicircular canal. The revival of the stapes mobilization operation by Rosen, in 1953, made the use of the microscope mandatory, although it was not used by the originators of the technique, Kessel (1878), Boucheron (1888) and Miot (1890). Mastoidectomies began to be performed with the surgical microscope and so were the tympanoplasty techniques that became known in the early 1950s. The stapes mobilization operation had varying results and was soon replaced by stapedectomy, first described by John Shea, Jr.; this was an operation that was always performed with the microscope. [ citation needed ]


Today  neurosurgeons  are very proud to use microscopes in their procedures. But it was not always so: many prestigious centers did not accept that idea and it had to be developed in relative isolation. In the late 1950s  William House  began to explore new techniques for temporal bone surgery. He developed the middle fossa approach and perfected the translabyrinthine approach and began to use these techniques to remove acoustic nerve tumors. The first neurosurgeon to make use of the surgical microscope was a Turkish emigrant,  Gazi Yasargil . In 1953 he studied neurovascular surgery during work with Prof. Hugo Krayenbühl in Switzerland. His ideas interested Dr. Pete Donaghy, who invited Yasargil to his microvascular laboratory in  Burlington, Vermont . After his return to  Zürich  in 1967 Yasargil concentrated on discovering clinical applications to their novel inventions. [ 1 ]  Publications on that topic:  Micro-Vascular Surgery [ 2 ]  and  Microsurgery Applied to Neurosurgery [ 3 ]  won him international recognition. His lifelong experiences with microsurgery were recapitulated in the four-volume textbook entitled simply  Microneurosurgery . [ 4 ]


Advances in the techniques and technology that popularized microsurgery began in the early 1960s to involve other medical areas. The first microvascular surgery, using a microscope to aid in the repair of blood vessels, was described by vascular surgeon, Julius H. Jacobson II of the University of Vermont in 1960. Using an operating microscope, he performed coupling of vessels as small as 1.4 mm and coined the term  microsurgery .  [ 5 ]  Hand surgeons at the  University of Louisville , Drs. Harold Kleinert and Mort Kasdan, performed the first revascularization of a partial digital amputation in 1963. [ 6 ]


Nakayama, a Japanese cardiothoracic surgeon, reported the first true series of microsurgical free-tissue transfers using vascularized intestinal segments to the neck for esophageal reconstruction after cancer resections using 3–4 mm vessels. [ 7 ]


Contemporary reconstructive microsurgery was introduced by an American  plastic surgeon , Dr.  Harry J. Buncke . In 1964, Buncke reported a  rabbit  ear replantation, famously using a garage as a lab/operating theatre and home-made instruments [ 8 ]
This was the first report of successfully using blood vessels 1 millimeter in size. In 1966, Buncke used microsurgery to transplant a primate's great toe to its hand. [ 9 ]


During the late sixties and early 1970s,  plastic surgeons  ushered in many new microsurgical innovations that were previously unimaginable. The first human microsurgical transplantation of the second toe to thumb was performed in February 1966 by Dr. Dong-yue Yang and Yu-dong Gu, in Shanghai, China. [ 10 ]  Great toe (big toe) to thumb was performed in April 1968 by Dr. John Cobbett, in England. [ 11 ]  In Australia work by Dr. Ian Taylor [ 12 ]  saw new techniques developed to reconstruct head and neck cancer defects with living bone from the hip or the  fibula .


A number of surgical specialties use microsurgical techniques. Otolaryngologists (ear, nose, throat and head and neck surgeons) perform microsurgery on structures of the inner ear and the vocal cords. Otolaryngologists and maxillofacial surgeons use microsurgical techniques when reconstructing defects from resection of head and neck cancers. Cataract surgery, corneal transplants, and treatment of conditions like glaucoma are performed by ophthalmologists. Urologists and gynecologists frequently now reverse vasectomies and tubal ligations to restore fertility.


Free tissue transfer is a  surgical reconstructive procedure  using microsurgery. A region of "donor" tissue is selected that can be isolated on a feeding artery and vein; this tissue is usually a composite of several tissue types (e.g.,  skin ,  muscle ,  fat ,  bone ). Common donor regions include the  rectus abdominis muscle ,  latissimus dorsi muscle ,  fibula , radial  forearm  bone and skin, and lateral arm skin. The composite tissue is transferred (moved as a  free flap  of tissue) to the region on the patient requiring reconstruction (e.g.,  mandible  after  oral cancer  resection,  breast  after cancer resection, traumatic tissue loss, congenital tissue absence). The vessels that supply the free flap are anastomosed with microsurgery to matching vessels ( artery  and  vein ) in the reconstructive site. The procedure was first done in the early 1970s and has become a popular "one-stage" (single operation) procedure for many surgical reconstructive applications.


Replantation  is the reattachment of a completely detached body part.  Fingers  and  thumbs  are the most common but the  ear ,  scalp ,  nose ,  face ,  arm  and  penis  have all been replanted. Generally replantation involves restoring blood flow through  arteries  and  veins , restoring the bony skeleton and connecting tendons and nerves as required.
Robert Malt and Charles Mckhann reported the first replantation of two human upper extremities by microvascular means in 1964, with the first arm replanted in a child after a train injury in 1962 in Boston. [ 13 ]
Initially, when the techniques were developed to make replantation possible, success was defined in terms of a survival of the amputated part alone. However, as more experience was gained in this field, surgeons specializing in replantation began to understand that survival of the amputated piece was not enough to ensure success of the replant. In this way, functional demands of the amputated specimen became paramount in guiding which amputated pieces should and should not be replanted. Additional concerns about the patient's ability to tolerate the long rehabilitation process that is necessary after replantation both on physical and psychological levels also became important. So, when fingers are amputated, for instance, a replantation surgeon must seriously consider the contribution of the finger to the overall function of the hand. In this way, every attempt will be made to salvage an amputated thumb, since a great deal of hand function is dependent on the thumb, while an index finger or small finger might not be replanted, depending on the individual needs of the patient and the ability of the patient to tolerate a long surgery and a long course of rehabilitation.


However, if an amputated specimen is not able to be replanted to its original location entirely, this does not mean that the specimen is unreplantable. In fact, replantation surgeons have learned that only a piece or a portion may be necessary to obtain a functional result, or especially in the case of multiple amputated fingers, a finger or fingers may be transposed to a more useful location to obtain a more functional result. This concept is called "spare parts" surgery.


Microsurgical techniques have played a crucial role in the development of transplantation immunological research because it allowed the use of rodent models, which are more appropriate for transplantation research (there are more reagents, monoclonal antibodies, knockout animals, and other immunological tools for mice and rats than other species). Before it was introduced, transplant immunology was studied in rodents using the skin transplantation model, which is limited by the fact that it is not vascularized. Thus, microsurgery represents the link between surgery and transplant immunological research.
The first microsurgical experiments (porto-caval anastomosis in the rat) were performed by Dr. Sun Lee (pioneer of microsurgery) at the University of Pittsburgh in 1958. After a short time, many models of organ transplants in rat and mice have been established. Today, virtually every rat or mouse organ can be transplanted with relative high success rate.
Microsurgery was also important to develop new techniques for transplantation, that would be later performed in humans. In addition, it allows reconstruction of small arteries in clinical organ transplantation (e.g. accessory arteries in cadaver liver transplantation, polar arteries in renal transplantation and in living liver donor transplantation).


Microsurgery has been used to treat several pathologic conditions leading to infertility such as tubal obstructions, vas deferens obstructions, and  varicocele , which is one of the most frequent cause of male infertility. Microsurgical drainages by placing microvascular bypasses between spermatic and inferior epigastric veins as proposed by  Flati  et al. have been successfully performed in treating male infertility due to varicocele. Microsurgical treatment has been shown to significantly improve fertility rate also in patients with recurrent varicocele who had previously undergone non-microsurgical treatments. [ 14 ]
 [ 15 ]


The  middle ear  is the portion of the  ear  medial to the  eardrum , and distal to the  oval window  of the cochlea (of the  inner ear ).


The mammalian middle ear contains three  ossicles  (malleus, incus, and stapes), which transfer the vibrations of the eardrum into waves in the fluid and membranes of the  inner ear .  The hollow space of the middle ear is also known as the  tympanic cavity  and is surrounded by the  tympanic part of the temporal bone . The  auditory tube  (also known as the Eustachian tube or the pharyngotympanic tube) joins the tympanic cavity with the nasal cavity ( nasopharynx ), allowing pressure to equalize between the middle ear and throat.


The primary function of the middle ear is to efficiently transfer acoustic energy from  compression waves  in air to fluid–membrane waves within the  cochlea .


The middle ear contains three tiny bones known as the  ossicles :  malleus ,  incus , and  stapes .  The ossicles were given their Latin names for their distinctive shapes; they are also referred to as the  hammer ,  anvil , and  stirrup , respectively. The ossicles directly couple sound energy from the eardrum to the  oval window  of the cochlea.  While the stapes is present in all  tetrapods , the malleus and incus  evolved from lower and upper jaw bones present in reptiles .


The ossicles are classically supposed to mechanically convert the vibrations of the  eardrum  into amplified pressure waves in the fluid of the  cochlea  (or  inner ear ), with a lever arm factor of 1.3. Since the effective vibratory area of the eardrum is about 14 fold larger than that of the oval window, the sound pressure is concentrated, leading to a pressure gain of at least 18.1. The eardrum is merged to the malleus, which connects to the incus, which in turn connects to the stapes. Vibrations of the stapes footplate introduce pressure waves in the  inner ear . There is a steadily increasing body of evidence that shows that the lever arm ratio is actually variable, depending on frequency. Between 0.1 and 1 kHz it is approximately 2, it then rises to around 5 at 2 kHz and then falls off steadily above this frequency. [ 1 ]  The measurement of this lever arm ratio is also somewhat complicated by the fact that the ratio is generally given in relation to the tip of the malleus (also known as the  umbo ) and the level of the middle of the stapes. The eardrum is actually attached to the malleus handle over about a 0.5 cm distance. In addition, the eardrum itself moves in a very chaotic fashion at frequencies >3 kHz. The linear attachment of the eardrum to the malleus actually smooths out this chaotic motion and allows the ear to respond linearly over a wider frequency range than a point attachment. The auditory ossicles can also reduce sound pressure (the inner ear is very sensitive to overstimulation), by uncoupling each other through particular muscles.


The middle ear efficiency peaks at a frequency of around 1 kHz. The combined  transfer function  of the outer ear and middle ear gives humans a peak sensitivity to frequencies between 1 kHz and 3 kHz.


The movement of the ossicles may be stiffened by two muscles. The  stapedius muscle , the smallest skeletal muscle in the body, connects to the stapes and is controlled by the  facial nerve ; the  tensor tympani muscle  is attached to the upper end of the medial surface of the handle of malleus [ 2 ]  and is under the control of the  medial pterygoid nerve  which is a branch of the  mandibular nerve  of the  trigeminal nerve . These muscles contract in response to loud sounds, thereby reducing the transmission of sound to the inner ear. This is called the  acoustic reflex .


Of surgical importance are two branches of the  facial nerve  that also pass through the middle ear space.  These are the horizontal portion of the facial nerve and the  chorda tympani .  Damage to the horizontal branch during ear surgery can lead to  paralysis of the face (same side of the face as the ear).  The chorda tympani is the branch of the facial nerve that carries taste from the  ipsilateral  half (same side) of the tongue.


Ordinarily, when sound waves in air strike liquid, most of the energy is reflected off the surface of the liquid.  The middle ear allows the  impedance matching  of sound traveling in air to acoustic waves traveling in a system of fluids and membranes in the inner ear.  This system should not be confused, however, with the propagation of sound as compression waves in liquid.


The  acoustic impedance  of air is about

 Z

 1

 =
 400

 P
 a
 ⋅
 s

 /

 m

 {\displaystyle Z_{1}=400\;\mathrm {Pa\cdot s/m} }

 , while the impedance of cochlear fluids (

 Z

 2

 =
 1.5
 ×

 10

 6

 P
 a
 ⋅
 s

 /

 m

 {\displaystyle Z_{2}=1.5\times 10^{6}\;\mathrm {Pa\cdot s/m} }

 ) is approximately equal to that of sea water. Because of this high impedance, only

 2

 Z

 1

 Z

 1

 +

 Z

 2

 =
 0.05
 %

 {\displaystyle {\frac {2Z_{1}}{Z_{1}+Z_{2}}}=0.05\%}

  of incident energy could be directly transmitted from the air to cochlear fluids.


The middle ear's impedance matching mechanism increases the efficiency of sound transmission. Two processes are involved:


Together, they amplify pressure by 26 times, or about 30 dB. The actual value is around 20 dB across 200 to 10000 Hz. [ 3 ] [ 4 ]


The middle ear couples sound from air to the fluid via the  oval window , using the principle of "mechanical advantage" in the form of the "hydraulic principle" and the "lever principle". [ 5 ]   The vibratory portion of the tympanic membrane (eardrum) is many times the surface area of the footplate of the  stapes  (the third ossicular bone which attaches to the oval window); furthermore, the shape of the articulated ossicular chain is a complex  lever , the long arm being the long process of the  malleus , the fulcrum being the body of the  incus , and the short arm being the lenticular process of the  incus .  The collected pressure of sound vibration that strikes the tympanic membrane is therefore concentrated down to this much smaller area of the footplate, increasing the force but reducing the velocity and displacement, and thereby coupling the acoustic energy.


The middle ear is able to dampen sound conduction substantially when faced with very loud sound, by noise-induced reflex contraction of the middle-ear muscles.


The middle ear is hollow in the tympanic cavity and Eustachian tube. In a high-altitude environment or on diving into water, there will be a pressure difference between the middle ear and the outside environment.  This pressure will pose a risk of bursting or otherwise damaging the tympanum (eardrum) if it is not relieved. If middle ear pressure remains low, the  eardrum  (tympanic membrane) may become  retracted  into the middle ear. [ citation needed ]   One of the functions of the  Eustachian tubes  that connect the middle ear to the  nasopharynx  is to help keep middle ear pressure the same as air pressure. The Eustachian tubes are normally pinched off at the nose end, to prevent being clogged with  mucus , but they may be opened by lowering and protruding the jaw; this is why  yawning  or chewing helps relieve the pressure felt in the ears when on board an aircraft.  Eustachian tube  obstruction may result in fluid build up in the middle ear, which causes a  conductive hearing loss .  Otitis media  is an inflammation of the middle ear.


The middle ear is well protected from most minor external injuries by its internal location, but is vulnerable to pressure injury ( barotrauma ).


Recent findings indicate that the middle ear mucosa could be subjected to  human papillomavirus  infection. [ 6 ]  Indeed, DNAs belonging to oncogenic HPVs, i.e., HPV16 and HPV18, have been detected in normal middle ear specimens, thereby indicating that the normal middle ear mucosa could potentially be a target tissue for HPV infection. [ 6 ]


The middle ear of  tetrapods  is  analogous  with the  spiracle  of fishes, an opening from the  pharynx  to the side of the head in front of the main gill slits. In fish embryos, the spiracle forms as a pouch in the pharynx, which grows outward and breaches the skin to form an opening; in most tetrapods, this breach is never quite completed, and the final vestige of tissue separating it from the outside world becomes the eardrum. The inner part of the spiracle, still connected to the pharynx, forms the eustachian tube. [ 7 ]


In  reptiles ,  birds , and early fossil tetrapods, there is a single auditory ossicle, the  columella  which is homologous with the stapes, or "stirrup" of mammals. This is connected indirectly with the eardrum via a mostly cartilaginous extracolumella and medially to the inner-ear spaces via a widened footplate in the fenestra ovalis. [ 7 ]  The columella is an evolutionary derivative of the bone known as the hyomandibula in fish ancestors, a bone that supported the skull and braincase.


The structure of the middle ear in living  amphibians  varies considerably and is often degenerate. In most  frogs and toads , it is similar to that of reptiles, but in other amphibians, the middle ear cavity is often absent. In these cases, the stapes either is also missing or, in the absence of an eardrum, connects to the  quadrate bone  in the skull, although, it is presumed, it still has some ability to transmit vibrations to the inner ear. In many amphibians, there is also a second auditory ossicle, the  operculum  (not to be confused with the  structure of the same name  in fishes). This is a flat, plate-like bone, overlying the fenestra ovalis, and connecting it either to the stapes or, via a special muscle, to the  scapula . It is not found in any other vertebrates. [ 7 ]


Mammals are unique in having  evolved a three-ossicle middle-ear  independently of the various single-ossicle middle ears of other land vertebrates, all during the Triassic period of geological history. Functionally, the mammalian middle ear is very similar to the single-ossicle ear of non-mammals, except that it responds to sounds of higher frequency, because these are better taken up by the inner ear (which also responds to higher frequencies than those of non-mammals). The malleus, or "hammer", evolved from the  articular  bone of the lower jaw, and the incus, or "anvil", from the quadrate. In other vertebrates, these bones form the primary jaw joint, but the expansion of the  dentary  bone in mammals led to the evolution of an entirely new jaw joint, freeing up the old joint to become part of the ear. For a period of time, both jaw joints existed together, one medially and one laterally. The evolutionary process leading to a three-ossicle middle ear was thus an "accidental" byproduct of the simultaneous evolution of the new, secondary jaw joint. In many mammals, the middle ear also becomes protected within a cavity, the  auditory bulla , not found in other vertebrates. A bulla evolved late in time and independently numerous times in different mammalian clades, and it can be surrounded by membranes, cartilage or bone. The bulla in humans is part of the  temporal bone . [ 7 ]


Recently found fossils such as  Morganucodon  show intermediary steps of middle ear evolution. A new morganucodontan-like species,  Dianoconodon youngi , shows parts of the  mandible  (= dentary) that permit an auditory function, although these bones are still attached to the mandible. [ 8 ]


Minimal-access cranial suspension  is a form of facial surgery or  rhytidectomy  used to reduce wrinkles and lift sagging facial tissue and originally developed in Belgium. [ 1 ]  Facial tissues are accessed via an incision before the ear. Sutures are then used to lift the underlying tissue. These sutures are then anchored to the deep  temporal   fascia  with  purse-string sutures . [ citation needed ]


The  nasal mucosa  lines the  nasal cavity . It is part of the  respiratory mucosa , the  mucous membrane  lining the  respiratory tract . [ 1 ] [ 2 ]  The nasal mucosa is intimately adherent to the  periosteum  or  perichondrium  of the  nasal conchae . It is continuous with the skin through the  nostrils , and with the  mucous membrane  of the nasal part of the  pharynx  through the  choanae . From the nasal cavity its continuity with the  conjunctiva  may be traced, through the  nasolacrimal  and  lacrimal ducts ; and with the  frontal ,  ethmoidal ,  sphenoidal , and  maxillary sinuses , through the several openings in the  nasal meatuses . The mucous membrane is thickest, and most vascular, over the  nasal conchae . It is also thick over the  nasal septum  where increased numbers of goblet cells produce a greater amount of  nasal mucus . It is very thin in the meatuses on the floor of the nasal cavities, and in the various  sinuses .  It is one of the most commonly infected tissues in adults and children. Inflammation of this tissue may cause significant impairment of daily activities, with symptoms such as stuffy nose, headache, mouth breathing, etc.


Owing to the thickness of the greater part of this  membrane , the nasal cavities are much narrower, and the middle and inferior nasal conchæ appear larger and more prominent than in the  skeleton ; also the various apertures communicating with the meatuses are considerably narrowed.


The  epithelium  of the nasal mucosa is of two types –  respiratory epithelium , and  olfactory epithelium  differing according to its functions. In the respiratory region it is columnar and ciliated. [ 3 ] [ 4 ]  Interspersed among the  columnar cells  are  goblet  or mucin cells, while between their bases are found smaller  pyramidal cells . Beneath the epithelium and its  basement membrane  is a fibrous layer infiltrated with lymph corpuscles, so as to form in many parts a diffuse  adenoid  tissue, and under this a nearly continuous layer of small and larger  glands , some mucous and some serous, the ducts of which open upon the surface. In the olfactory region the mucous membrane is yellowish in color and the  epithelial cells  are columnar and non-ciliated; they are of two kinds, supporting cells and  olfactory cells . The supporting cells contain oval nuclei, which are situated in the deeper parts of the cells and constitute the zone of oval nuclei; the superficial part of each cell is columnar, and contains granules of yellow  pigment , while its deep part is prolonged as a delicate process which ramifies and communicates with similar processes from neighboring cells, so as to form a net-work in the mucous membrane. Lying between the deep processes of the supporting cells are a number of  bipolar nerve cells , the olfactory cells, each consisting of a small amount of granular  protoplasm  with a large spherical  nucleus , and possessing two processes—a superficial one which runs between the columnar epithelial cells, and projects on the surface of the mucous membrane as a fine, hair-like process, the olfactory hair; the other or deep process runs inward, is frequently beaded, and is continued as the  axon  of an olfactory nerve fiber. Beneath the epithelium, and extending through the thickness of the mucous membrane, is a layer of tubular, often branched, glands, the  glands of Bowman , identical in structure with  serous glands . The epithelial cells of the  nose ,  fauces  and respiratory passages play an important role in the maintenance of an equable temperature, by the moisture with which they keep the surface always slightly lubricated. [ 4 ]


A  myringotomy  is a surgical procedure in which an incision is created in the  eardrum  (tympanic membrane) to relieve pressure caused by excessive buildup of fluid, or to drain  pus  from the  middle ear . A  tympanostomy tube  may be inserted through the eardrum to keep the middle ear aerated for a prolonged time and to prevent reaccumulation of fluid. Without the insertion of a tube, the incision usually heals spontaneously within two to three weeks.  Depending on the type, the tube is either naturally extruded in 6 to 12 months or removed during a minor procedure. [ 1 ]


Those requiring myringotomy usually have an obstructed or dysfunctional  eustachian tube  that is unable to perform drainage or ventilation in its usual fashion. Before the invention of antibiotics, myringotomy without tube placement was also used as a major treatment of severe  acute otitis media  (middle ear infection). [ 1 ]


The words  myringotomy ,  tympanotomy ,  tympanostomy , and  tympanocentesis  overlap in meaning. The first two are always synonymous, and the third is often used synonymously. [ 2 ]  The core idea with each is cutting a hole in the eardrum to allow fluid to pass through it. Sometimes a distinction is drawn between myringotomy/tympanotomy and tympanostomy, in parallel with the general distinction between an  -otomy  (cutting) and an  -ostomy  (creating a  stoma  with some degree of permanence or semipermanence). In this distinction, only a tympanostomy involves  tympanostomy tubes  and creates a semipermanent stoma. This distinction in usage is not always made. The word  tympanocentesis  specifies that  centesis  (the removal of fluid [ 3 ] ) is being done.


Etymologically,  myringotomy  ( myringo- , from Latin  myringa  "eardrum", [ 4 ]  +  -tomy ) and  tympanotomy  ( tympano-  +  -tomy ) both mean "eardrum cutting", and  tympanostomy  ( tympano-  +  -stomy  means "making an eardrum stoma".


In 1649,  Jean Riolan the Younger  accidentally pierced a patient's eardrum while cleaning it with an  ear spoon .  Surprisingly, the patient's hearing improved. There are also reports from the 17th and 18th centuries describing separate experiments exploring the function of the eardrum. [ 5 ]   In particular, the animal experiments of  Thomas Willis  were expanded upon by Sir  Astley Cooper , who presented two papers to the  Royal Society  in 1801 on his observations that myringotomy could improve hearing. [ 6 ]   First, he showed that two patients with perforations of both eardrums could hear perfectly well, despite conventional wisdom that this would result in deafness. Second, he demonstrated that deafness caused by obstruction of the Eustachian tube could be relieved by myringotomy, which equalized the pressure on each side of the tympanic membrane. [ citation needed ]


Widespread inappropriate use of the procedure later led to it falling out of use.  However, it was reintroduced by  Hermann Schwartze  in the 19th century.  An inherent problem became recognized, namely the tendency of the tympanic membrane to heal spontaneously and rapidly, reversing the beneficial effects of the perforation.  In order to prevent this, a tympanostomy tube, initially made of gold foil, was placed through the incision to prevent it from closing. In 1819 the French physician Antoine Saissy (1756–1822) tried to keep the myringotomy unsuccessfully open with Catgut. [ 7 ] [ 8 ]   Ádám Politzer , a Hungarian-born  otologist  practicing in Vienna, experimented with rubber in 1886.  The German otologist Rudolf Voltolini (1819–1889) created in 1874 a grommet made of gold and later on one made of aluminium. [ 8 ] [ 9 ]  The vinyl tube used today was introduced by Beverly Armstrong in 1954. [ 8 ]


There are numerous indications for tympanostomy in the pediatric age group, [ 1 ] [ 10 ]  the most frequent including chronic  otitis media with effusion (OME)  which is unresponsive to antibiotics, and recurrent  otitis media .  Adult indications [ 1 ] [ 11 ] [ 12 ]  differ somewhat and include Eustachian tube dysfunction with recurrent signs and symptoms, including fluctuating hearing loss,  vertigo ,  tinnitus , and a severe retraction pocket in the  tympanic membrane .  Recurrent episodes of  barotrauma , especially with flying, diving, or  hyperbaric chamber treatment , may merit consideration. [ citation needed ]


Myringotomy is usually performed as an outpatient procedure.  General anesthesia  is preferred in children, while  local anesthesia  suffices for adults.  The ear is washed and a small incision made in the eardrum.  Any fluid that is present is then aspirated, the tube of choice inserted, and the ear packed with cotton to control any slight bleeding that might occur.  This is known as conventional (or  cold knife ) myringotomy and usually heals in one to two days. [ 13 ]


A new variation (called  tympanolaserostomy  or  laser-assisted tympanostomy ) uses a  CO 2  laser , and is performed with a computer-driven laser and a video monitor to pinpoint a precise location for the hole.  The laser takes one-tenth of a second to create the opening, without damaging surrounding skin or other structures.  This perforation remains  patent  for several weeks and provides ventilation of the middle ear without the need for tube placement. [ 14 ]


Though laser myringotomies maintain patency slightly longer than cold-knife myringotomies (two to three weeks for laser and two to three days for cold knife without tube insertion), [ 15 ]  they have not proven to be more effective in the management of effusion.  One randomized controlled study found that laser myringotomies are safe but less effective than ventilation tube in the treatment of chronic OME. [ 16 ]   Multiple occurrences in children, a strong history of allergies in children, the presence of thick  mucoid  effusions, and history of tympanostomy tube insertion in adults, make it likely that laser tympanostomy will be ineffective. [ 13 ]


Various tympanostomy tubes are available. Traditional metal tubes have been replaced by more popular silicon, titanium, polyethylene, gold, stainless steel, or fluoroplastic tubes.  More recent ones are coated with antibiotics and  phosphorylcholine . [ citation needed ]


There is little scientific evidence to guide the care of the ear after tubes have been inserted.  A single, randomized trial found statistical benefit to using ear protective devices when swimming although the size of the benefit was quite small. [ 17 ]   In the absence of strong evidence, general opinion has been against the use of ear protection devices.  However, protection such as cotton covered with petroleum jelly, ear plugs, or ear putty is recommended for swimming in dirty water (lakes, rivers, oceans, or non-chlorinated pools) to prevent ear infections.  For bathing, shampooing, or surface-water swimming in chlorinated pools, no ear protection is recommended.


The placement of tubes is not a cure.  If middle ear disease has been severe or prolonged enough to justify tube placement, there is a strong possibility that the child will continue to have episodes of middle ear inflammation or fluid collection.  There may be early drainage through the tube ( tube otorrhea ) in about 15% of patients in the first two weeks after placement, and developing in 25% more than three months after insertion, although usually not a longterm problem. [ 18 ]   Otorrhea is considered to be secondary to bacterial colonization.  The most commonly isolated organism is  Pseudomonas aeruginosa , while the most troublesome is  Methicillin-resistant  Staphylococcus aureus  (MRSA) . Some practitioners use topical antibiotic drops in the postoperative period, but research shows that this practice does not eradicate the bacterial  biofilm . [ 1 ]   A laboratory study showed that tubes covered in the antibiotic  vancomycin  prevented in-vitro formation of MRSA biofilm as compared to noncoated ones, [ 19 ]  although no study has been conducted on humans yet.  Comparing phosphorylcholine-coated fluoroplastic tympanostomy tubes to uncoated fluoroplastic tympanostomy tubes showed no statistically significant difference in the incidence of post-operative otorrhea, tube blockage, or extrusion. [ 20 ]


Evidence suggests that tympanostomy tubes only offer a short-term hearing improvement in children with simple OME who have no other serious medical problems.  No effect on speech and language development has yet been shown. [ 21 ]


A retrospective study of success rates in 96 adults and 130 children with otitis media treated with CO 2  laser myringotomy showed about a 50% cure rate at six months in both groups. [ 13 ]   To date, there have been no published systematic reviews.


Balloon dilation  eustachian tuboplasty (BDET), a new treatment, has proven to be effective in treating OME secondary to  eustachian tube  dysfunction. [ 22 ] [ 23 ] [ 24 ]  However, the number of patients in the studies cited, 22 and 8 respectively and 18 in the tympanometric study, is extremely small and simply points to the need for large, well-controlled studies.


The  nasal bones  are two small oblong  bones , varying in size and form in different individuals; they are placed side by side at the middle and upper part of the  face  and by their junction, form the  bridge  of the upper one third of the  nose .


Each has two surfaces and four borders.


There is heavy  variation  in the structure of the nasal bones, accounting for the differences in sizes and shapes of the nose seen across different people. Angles, shapes, and configurations of both the bone and cartilage are heavily varied between individuals. Broadly, most nasal bones can be categorized as "V-shaped" or "S-shaped" but these are not  scientific  or medical categorizations. When viewing  anatomical drawings  of these bones, consider that they are unlikely to be accurate for a majority of people. [ 1 ]


The two nasal bones are joined at the midline  internasal suture  and make up the  bridge of the nose .


The  outer surface  is  concavo-convex  from above downward, convex from side to side; it is covered by the  procerus  and  nasalis  muscles, and perforated about its center by the  nasal foramen , a small passageway for the transmission of a small  vein  from the overlying soft tissues.


The  inner surface  is concave from side to side, and is traversed from above downward, by a groove for the passage of a branch of the  nasociliary nerve .


The nasal articulates with four bones: two of the cranium, the  frontal  and  ethmoid , and two of the face, the opposite nasal and the  maxilla .


In primitive  bony fish  and  tetrapods , the nasal bones are the most anterior of a set of four paired bones forming the  roof of the skull , being followed in sequence by the frontals, the  parietals , and the  postparietals . Their form in living species is highly variable, depending on the shape of the head, but they generally form the roof of the snout or beak, running from the nostrils to a position short of the orbits. In most animals, they are generally therefore proportionally larger than in humans or great apes, because of the shortened faces of the latter.  Turtles , unusually, lack nasal bones, with the  prefrontal bones  of the orbit reaching all the way to the nostrils. [ 2 ]


The  nasal cartilages  are structures within the nose that provide form and support to the nasal cavity. [ 1 ]  The nasal cartilages are made up of a flexible material called  hyaline cartilage  (packed collagen) in the distal portion of the nose. [ 2 ]  There are five individual cartilages that make up the nasal cavity:  septal nasal cartilage ,  lateral nasal cartilage ,  major alar cartilage  (greater alar cartilage, or cartilage of the aperture),  minor alar cartilage  (lesser alar cartilage, sesamoid, or accessory cartilage), and  vomeronasal cartilage  (Jacobson's cartilage).


The nasal cartilages associate with other cartilage structures of the nose or with bones of the facial skeleton. These associations create vent-like structures within the nose so that air can flow from the nasal cavity to the lungs or vice versa. Therefore, the nasal cartilages are structures that aid the body in respiratory functions to intake oxygen or expire carbon dioxide.


Abnormalities or defects in the nasal cartilages affect airflow through the nasal cavity, resulting in respiratory issues. Surgical techniques have been produced to adjust the position or repair the nasal cartilages so that maximal airflow is once again accomplished. Some of these surgical techniques include:  septoplasty  (restructuring the septal nasal cartilage), upper lateral cartilage repositioning (restructuring the lateral nasal cartilage), and sliding alar cartilage (restructuring the major alar cartilage).  Rhinoplasty , which is the surgical reconstruction of the nose, has increased in recent popularity for functional and social purposes.


Other mammals also contain nasal cartilages in order to maintain structure and function for the nasal cavity. The orientation of the nasal cartilages can produce different shapes and sizes of the nostrils and nasal cavities. For the most part, animals contain similar cartilage structures within the nose but vary in the number of different cartilage structures they have. Donkeys, buffalo, and camels have a variety of cartilage structures that are analogous to humans but they all lack septal nasal cartilages. Instead, they have multiple components merging together to form the  nasal septum . Even though nasal cartilages differ between species, they all aid in the function of the  respiratory system .


The  septal nasal cartilage  is a flat, quadrilateral piece of hyaline cartilage that separates both nasal cavities from one another. [ 3 ]  The septal nasal cartilage fits in a place between the perpendicular plate of the ethmoid and vomer bones while also being covered by an internal  mucous membrane . The superior portion of the septal nasal cartilage attaches to the nasal bones, while the inferior portion attaches to the alar cartilages via fibrous tissues. The septal nasal cartilage separates both right and left nasal cavities, which allows air to pass through them. Providing two cavities generates turbulence within the tight spaces, allowing air to flow quicker bidirectionally. The septal nasal cartilage is also the main structure that provides the orientation of the nose, being the midline structure of the organ. With an offset septal nasal cartilage, the nose will appear crooked to the viewer. A crooked nose can block airflow coming from the nares to the lungs or vice versa. [ 4 ]  This can lead to respiratory issues due to low oxygen but high carbon dioxide counts within the body. A surgical procedure to correct this issue is called  septoplasty .


The  lateral nasal cartilage  is a wing-like expansion extending out from the septal nasal cartilage. [ 5 ]  The lateral nasal cartilage lies inferiorly to the nasal bones while sitting superiorly to the major alar cartilage, separated by a narrow fissure. The lateral nasal cartilage and major alar cartilage curl up upon interaction with one another, forming a tight connection through fibrous tissues. Like the septal nasal cartilage, the lateral nasal cartilage is composed of hyaline cartilage. Hyaline cartilage provides form and flexibility within a specific structure.


The superior portion of the lateral nasal cartilage fuses with the septum to provide support within the nasal cavities. With a collapse of the lateral nasal cartilage, the inner nasal valve could become obstructed and prevent the movement of airflow throughout. [ 6 ]  A new surgical technique to reposition the lateral nasal cartilage has been constructed to relieve the site of obstruction within the inner nasal valve and regain maximal airflow throughout the nose (upper lateral cartilage repositioning).


The  major alar cartilages  are positioned with one structure on each side of the nasal tip. [ 7 ]  Superiorly, the major alar cartilages are connected to the lateral nasal cartilage via fibrous tissues. Composed of hyaline cartilage, these structures are very thin and folded to form the lateral and medial crus. The medial crus is the inner portion of the major alar cartilages that are situated perpendicularly to the septal nasal cartilage. The lateral crus is the outer portion of the major alar cartilages that associate with the  ala of the nose .


Both crus come together to form an oval tip at each nostril. Both sides of the major alar cartilages merge together to form a notch at the tip, which is referred to as the apex of the nose. With the formation of the medial and lateral walls within the nares, the major alar cartilages function to hold open each naris. This allows maximal airflow to reach the nasal valve, allowing optimal respiration. Due to weakness corresponding with the lateral crus in certain individuals, a technique called sliding alar cartilage (SAC) has been a procedure practiced to restructure and support the nasal tip. [ 8 ]


The  minor alar cartilages  are 3 to 4 small hyaline cartilage pieces on both sides of the nose that sit between the lateral nasal cartilage and the major alar cartilage. [ 9 ]  Associated within the ala of the nose, these small structures are contained within the most dorsal part of the ala. Also known by its other name, "accessory cartilage", these structures aid to provide form and strength at the base of the nares in conjunction with the major alar cartilage.


The  vomeronasal cartilage  is a thin piece of hyaline cartilage that attaches to the vomer and extends to the septal nasal cartilage. [ 10 ]  This structure is associated with the  vomeronasal organ , which is part of the accessory olfactory system. This associated organ plays an important role in the sense of smell by being lined with similar epithelium to that of the olfactory region of the nose. The vomeronasal cartilage is another small component of the nose that provides strength and structure.


With emerging technological advancements, reconstruction and surgical techniques have been developed to adjust the lifestyle and health of individuals.  Rhinoplasty  is one of the surgical practices that has become more common in the modern era. Some rhinoplastic procedures include septoplasty, sliding alar cartilage, and upper lateral cartilage repositioning. These procedures aid in cosmetic as well as functional issues involving the nose. Other reconstruction procedures are being produced and tested as the knowledge for nasal cartilages increase.


Septoplasty  is a surgical procedure that straightens the septal nasal cartilage within the center of the nose. [ 11 ]  With a crooked septum, it is more difficult for an individual to breathe and the risk for getting a sinus infection increases. Also called a  deviated septum , a crooked nose will block one or both sides of the nose, affecting the quality of life. [ 4 ]  However, a deviated septum is very common and does not always create respiratory issues. Respiratory issues usually occur in more severe cases, requiring surgery to repair. [ 11 ]  Surgery is also permitted to individuals that seek cosmetic changes due to moderate cases of a deviated septum. Surgery may require a surgeon to cut and remove parts of the septal nasal cartilages, replacing them later in a reconstructed format. This will allow the individual to receive more airflow through the nostrils when the surgery fully heals after 3 to 6 months. However, there are some risks correlated with this surgical procedure. These risks include a change in the shape of the nose, excessive bleeding, vacant space in the septum, trouble smelling, blood clots that need to be removed, and numbness by the facial region. Smoking can also cause further damage during the healing process of septoplastic surgery.


The upper lateral cartilage repositioning procedure is done to move the lateral nasal cartilage from blocking the nasal valve. [ 6 ]  The nasal valve is the smallest airway within the nose and is a common site for obstruction. Other surgical procedures open up this air way by employing grafts to separate the septal nasal and lateral nasal cartilages from one another. Grafts need to be used permanently due to the complications of removing such a device. The upper lateral cartilage repositioning technique deploys a temporary stint that repositions the lateral nasal cartilage, lets it heal/be stationary due to scar tissue formation, then is removed. This open rhinoplastic procedure allows the nose to heal to an optimal position without the permanent use of man-made hardware. This procedure is just one way to resolve issues involving lateral nasal cartilage deformities. Other procedures are being produced and improved upon in order to generate the simplest and most safe surgical procedure.


The sliding alar cartilage is a procedure to strengthen and support the nasal tip. [ 8 ]  This medical practice is completed on the greater alar cartilage in order to reshape this structure. The greater alar cartilages can become very weak or have deformities, creating respiratory issues. Other medical procedures that reshape the greater alar cartilages use grafts or cartilage re-sectioning. The SAC procedure is completed within two to three minutes. In that timeframe, the tip of the nose is cut open, the greater alar cartilage is manipulated to preserve the scroll area, providing strength and structure, then the incision is sutured back up. [ 12 ]  This simple technique creates tip definition while maintaining airway function. While there are other procedures to strengthen the greater alar cartilage, the SAC procedure is gaining momentum into common rhinoplastic operations.


The  nasal cavity  is a large, air-filled space above and behind the  nose  in the middle of the  face . The  nasal septum  divides the cavity into two cavities, [ 1 ]  also known as  fossae . [ 2 ]  Each cavity is the continuation of one of the two  nostrils . The nasal cavity is the uppermost part of the  respiratory system  and provides the  nasal passage  for inhaled air from the  nostrils  to the  nasopharynx  and rest of the  respiratory tract .


The  paranasal sinuses  surround and drain into the nasal cavity.


The term "nasal cavity" can refer to each of the two cavities of the nose, or to the two sides combined.


The lateral wall of each nasal cavity mainly consists of the  maxilla . However, there is a deficiency that is compensated for by the perpendicular plate of the  palatine bone , the  medial pterygoid plate , the  labyrinth of ethmoid  and the  inferior concha .  The  paranasal sinuses  are connected to the nasal cavity through small orifices called  ostia . Most of these ostia communicate with the nose through the lateral nasal wall, via a semi-lunar depression in it known as the  semilunar hiatus . The hiatus is bound laterally by a projection known as the  uncinate process . This region is called the  ostiomeatal complex . [ 3 ]


The roof of each nasal cavity is formed in its upper third to one half by the  nasal bone  and more inferiorly by the junctions of the upper lateral cartilage and nasal septum.  Connective tissue and skin cover the bony and cartilaginous components of the  nasal dorsum .


The floor of the nasal cavities, which also form the roof of the mouth, is made up by the bones of the hard palate: the horizontal plate of the palatine bone posteriorly and the palatine process of the maxilla anteriorly. The most anterior part of the nasal cavity is the  nasal vestibule . [ 4 ]  The vestibule is enclosed by the  nasal cartilages  and lined by the same  epithelium  of the  skin  (stratified squamous, keratinized). Within the vestibule, this changes into the typical respiratory epithelium that lines the rest of the nasal cavity and  respiratory tract . Inside the  nostrils  of the vestibule are the  nasal hair , which filter dust and other matter that are breathed in. The back of the cavity blends, via the  choanae , into the  nasopharynx .


The nasal cavity is divided in two by the vertical  nasal septum . On the side of each nasal cavity are three horizontal outgrowths called  nasal conchae  (singular "concha") or turbinates. These turbinates disrupt the airflow, directing air toward the  olfactory epithelium  on the surface of the turbinates and the septum. The  vomeronasal organ  is located at the back of the  septum  and has a role in  pheromone  detection.


The nasal cavity has a  nasal valve area  that includes an  external nasal valve  and an  internal nasal valve . The external nasal valve is bounded medially by the  columella , laterally by the  lateral nasal cartilage , and posteriorly by the nasal sill. [ 5 ]  The internal nasal valve is bounded laterally by the caudal border of the lateral nasal cartilage, medially by the dorsal  nasal septum , and inferiorly by the anterior border of the  inferior turbinate . [ 6 ]  The internal nasal valve is the narrowest region of the nasal cavity and is the primary site of nasal resistance. [ 7 ]


The nasal cavity is divided into two segments: the respiratory segment and the olfactory segment.


There is a rich blood supply to the nasal cavity.
Blood supply comes from branches of both the  internal  and  external carotid artery , including branches of the  facial artery  and  maxillary artery . The named arteries of the nose are:


Innervation  of the nasal cavity responsible for the  sense of smell  is via the  olfactory nerve , which sends microscopic fibers from the  olfactory bulb  through the  cribriform plate  to reach the top of the nasal cavity.


General sensory innervation is by branches of the  trigeminal nerve  (V 1  and V 2 ):


The nasal cavity is innervated by autonomic fibers.  Sympathetic  innervation to the blood vessels of the mucosa causes them to  constrict , while the control of secretion by the  mucous glands  is carried on  postganglionic   parasympathetic  nerve fibers originating from the  facial nerve .


The two nasal cavities condition the air to be received by the other areas of the  respiratory tract . Owing to the large surface area provided by the  nasal conchae  (also known as turbinates), the air passing through the nasal cavity is warmed or cooled to within 1 degree of  body temperature . In addition, the air is humidified, and dust and other particulate matter is removed by  nasal hair  in the nostrils. The entire mucosa of the nasal cavity is covered by a blanket of mucus, which lies superficial to the microscopic cilia and also filters inspired air. The  cilia  of the  respiratory epithelium  move the secreted mucus and particulate matter posteriorly towards the  pharynx  where it passes into the  esophagus  and is digested in the stomach. The nasal cavity also houses the sense of smell and contributes greatly to taste sensation through its posterior communication with the mouth via the  choanae .


Diseases of the nasal cavity include  viral ,  bacterial  and  fungal  infections, nasal cavity  tumors , both benign and much more often malignant, as well as inflammations of the  nasal mucosa .
Many problems can affect the nose, including:


The  nasal  glands  are the  seromucous glands  in the  respiratory  region of the  nasal mucous membrane . [ 2 ]  The three major types of nasal glands are anterior serous glands, seromucous glands, and Bowman glands. [ 3 ]


The anterior nasal glands help moisturize the nasal mucosa. [ 3 ]


The seromucous glands are found primarily in the anterior nasal cavity, and they are also found within the nasal cavity. [ 3 ]


The Bowman glands are serous glands that help the olfactory region with smelling. [ 3 ]


In  anatomy , the term  nasal meatus [ 1 ]  can refer to any of the three  meatuses  (passages) through the  skull ' s  nasal cavity : the  superior meatus  ( meatus nasi superior ),  middle meatus  ( meatus nasi medius ), and  inferior meatus  ( meatus nasi inferior ).


The nasal meatuses are the spaces beneath each of the corresponding  nasal conchae . In the case where a fourth,  supreme nasal concha  is present, there is a fourth  supreme nasal meatus .


The superior meatus is the smallest of the three. It is a narrow cavity located obliquely below the  superior concha . This meatus is short, lies above and extends from the middle part of the  middle concha  below. From behind, the  sphenopalatine foramen  opens into the cavity of the superior meatus and the meatus communicates with the posterior  ethmoidal cells . Above and at the back of the  superior concha  is the  sphenoethmoidal recess  which the  sphenoidal sinus  opens into. The superior meatus occupies the middle third of the  nasal cavity’s  lateral wall.


The middle meatus is the middle-sized and located nasal opening, lying underneath the middle concha and above the  inferior concha  where the meatus extends along its length. On it is a curved fissure, the  hiatus semilunaris , limited below by the edge of the  uncinate process of the ethmoid  and above by an elevation named the  bulla ethmoidalis ; the middle  ethmoidal cells  are contained within this bulla and open on or near to it.


Through the hiatus semilunaris the meatus communicates with a curved passage termed the  infundibulum , which communicates in front with the anterior ethmoidal cells and in rather more than fifty percent of skulls is continued upward as the frontonasal duct into the frontal air-sinus; when this continuity fails, the frontonasal duct opens directly into the anterior part of the meatus.


Below the bulla ethmoidalis and hidden by the uncinate process of the ethmoid is the opening of the  maxillary sinus  (ostium maxillare); an accessory opening is frequently present above the posterior part of the inferior nasal concha.


The inferior meatus is the largest of the three. It lies below the inferior concha and above the nasal cavity. It extends most of the length of the nasal cavity’s lateral wall. It is broader in the front than at the back, and presents anteriorly the lower orifice of the  nasolacrimal canal .


Nasal polyps  are  noncancerous growths  within the  nose  or  sinuses . [ 1 ]  Symptoms include trouble breathing through the nose,  loss of smell , decreased taste,  post nasal drip , and a  runny nose . [ 1 ]  The growths are  sac-like , movable, and nontender, though face pain may occasionally occur. [ 1 ]  They typically occur in both nostrils in those who are affected. [ 1 ]  Complications may include  sinusitis  and broadening of the nose. [ 2 ]


The exact cause is unclear. [ 1 ]  They may be related to chronic  inflammation  of the lining of the sinuses. [ 1 ]  They occur more commonly among people who have  allergies ,  cystic fibrosis ,  aspirin sensitivity , or certain infections. [ 1 ]  The polyp itself represents an overgrowth of the mucous membranes. [ 1 ]  Diagnosis may be accomplished by looking up the nose. [ 1 ]  A  CT scan  may be used to determine the number of polyps and help plan surgery. [ 1 ]


Treatment is typically with  steroids , often in the form of a  nasal spray . [ 1 ]  If this is not effective,  surgery  may be considered. [ 1 ]  The condition often recurs following surgery; thus, continued use of a steroid nasal spray is often recommended. [ 1 ]   Antihistamines  may help with symptoms but do not change the underlying disease. [ 1 ]   Antibiotics  are not required for treatment unless an infection occurs. [ 1 ]


About 4% of people currently have nasal polyps while up to 40% of people develop them at some point in their life. [ 1 ]  They most often occur after the age of 20 and are more frequent in males than females. [ 1 ]  Nasal polyps have been described since the time of the  Ancient Egyptians . [ 4 ]


Symptoms of polyps include  nasal congestion ,  sinusitis ,  loss of smell , thick nasal discharge, facial pressure, nasal speech, and mouth breathing. [ 5 ]  Recurrent  sinusitis  can result from polyps. [ 2 ]  Long-term, nasal polyps can cause destruction of the nasal bones and broadening of the nose. [ 2 ]


As polyps grow larger, they eventually prolapse into the  nasal cavity , resulting in symptoms. [ 6 ]  The most prominent symptoms of nasal polyps is blockage of the nasal passage. [ 7 ]  People with nasal polyps due to  aspirin intolerance  often have a disease known as  aspirin-exacerbated respiratory disease , which consists of asthma and chronic nasal polyps along with a hypersensitivity reaction to aspirin. [ 5 ]


The exact cause of nasal polyps is unclear. [ 1 ]  They are, however, commonly associated with conditions that cause long term  inflammation  of the sinuses. [ 8 ]  This includes  chronic rhinosinusitis ,  asthma ,  aspirin  sensitivity, and  cystic fibrosis . [ 8 ]


Various additional diseases associated with polyp formation include: [ 9 ]


Chronic rhinosinusitis  is a common medical condition characterized by symptoms of sinus inflammation lasting at least 12 weeks. The cause is unknown and the role of microorganisms remains unclear. It can be classified as either with or without nasal polyposis. [ 8 ]


Cystic fibrosis  (CF) is the most common cause of nasal polyps in children. Therefore, any child under 12 to 20 years old with nasal polyps should be tested for CF. [ 7 ] [ 10 ]  Half of people with CF will experience extensive polyps leading to nasal obstruction and requiring aggressive management. [ 7 ]


The true cause of nasal polyps is unknown, but they are thought to be due to recurrent infection or inflammation. [ 2 ]  Polyps arise from the lining of the sinuses. Nasal mucosa, particularly in the region of  middle meatus  becomes swollen due to collection of extracellular fluid. This extracellular fluid collection causes polyp formation and protrusion into the nasal cavity or sinuses. Polyps which are sessile in the beginning become  pedunculated  due to gravity. [ 11 ]


In people with nasal polyps due to  aspirin  or  NSAID  sensitivity, the underlying mechanism is due to disorders in the metabolism of  arachidonic acid . Exposure to  cycloxygenase inhibitors  such as aspirin and NSAIDs leads to shunting of products through the lipoxygenase pathway leading to an increased production of products that cause inflammation. In the airway, these inflammatory products lead to symptoms of asthma such as wheezing as well as nasal polyp formation. [ 12 ]


Nasal polyps can be seen on physical examination inside of the nose and are often detected during the evaluation of symptoms. On examination, a polyp will appear as a visible mass in the nostril. [ 5 ]  Some polyps may be seen with anterior rhinoscopy (looking in the nose with a nasal speculum and a light), but frequently, they are farther back in the nose and must be seen by nasal  endoscopy . [ 12 ]  Nasal endoscopy involves passing a small, rigid camera with a light source into the nose. An image is projected onto a screen in the office so the doctor can examine the nasal passages and sinuses in greater detail. The procedure is not generally painful, but the person can be given a spray decongestant and local anesthetic to minimize discomfort. [ 13 ]


Attempts have been made to develop scoring systems to determine the severity of nasal polyps. Proposed staging systems take into account the extent of polyps seen on endoscopic exam and the number of sinuses affected on CT imaging. This staging system is only partially validated, but in the future, may be useful for communicating the severity of disease, assessing treatment response, and planning treatment. [ 6 ]


There are two primary types of nasal polyps: ethmoidal and antrochoanal. Ethmoidal polyps arise from the  ethmoid sinuses  and extend through the  middle meatus  into the nasal cavity. Antrochoanal polyps usually arise in the  maxillary sinus  and extend into the nasopharynx and represent only 4–6% of all nasal polyps. [ 7 ]


However, antrochoanal polyps are more common in children comprising one-third of all polyps in this population. Ethmoidal polyps are usually smaller and multiple while antrochoanal polyps are usually single and larger. [ 7 ]


CT scan can show the full extent of the polyp, which may not be fully appreciated with physical examination alone. Imaging is also required for planning surgical treatment. [ 7 ]  On a  CT scan , a nasal polyp generally has an attenuation of 10–18  Hounsfield units , which is similar to that of  mucus . Nasal polyps may have  calcification . [ 14 ]