The Nose

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The Nose
Dorsum
Columella skin that seperates the naris
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External Nose
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Internal Nose
Vestibule
Nasal Cavity Proper

• Skin
• Very sensitive to pain
• Hair (Vibrissa)
• Limen nasi

• Mucosa - Respiratory and Olfactory
• Not so sensitive to pain

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Nasal Cavity

• Piriform aperture
• Tear drop shaped boney opening to the nasal
  cavity
• Nasal septum divides to cavities

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Bones that contribute to the nose and nasal cavity

• Nasal
• Frontal
• Maxilla
• Ethmoid
• Inferior Concha

• Sphenoid
• Palatine
• Vomer
• Lacrimal

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Bones of the Nasal walls

• Roof of cavity is made up of four bones
• Anterior frontal nasal
• Middle ethmoidal (cribriform plate)
• Posterior Sphenoid
• Lateral Wall
• Superior and middle concha are ethmoidal bone
• Inferior concha is its own bone
• Small piece of lacrimal bone can be observed
• Floor
• Same bones as hard palate

frontal
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Bones of the Septum

• cartilage
• Septal cartilage extends into vestibule
• Vomeronasal cartilageif present extends off vomer
  bone
• Ethmoid
• Perpendicular plate extends down from cribriform
  plate
• Crista galli is a superior extension
• Vomer bone
• Triangle o f bone in inferior posterior nasal
  septum
• Palatine and Maxilla
• form ridges that extend up into nasal cavity
• Vomer bone slots into these crests

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Nasal Concha

• There are three (sometimes four) turbinates on
  the lateral wall (called concha)
• Inferior,Middle, Superior and Supreme (if
  present)
• Concha are covered in respiratory epithelium (or
  olfactory epithelium near cribriform plate.
• Epithelium serves for heat exchange and to
  humidify air
• Bowman's glands secret mucus which coats
  epithelium
• Microvilli of epithelium beat down and back to
  move the mucus towards the nasopharynx.
• Spaces that allow air flow are meatus and named
  for the concha above them
• Note space superior and posterior to superior
  concha is the sphenoethmoidal recess
• Common meatus is the space between all concha and
  the septal wall

Inferior meatus
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Nasal Concha
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Nasal Concha

• a) Superior concha
• b) Middle concha
• c) Inferior concha
• Superior meatus
• Middle meatus
• Common meatus
• Inferior meatus

a
1
b
2
3
c
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Nerves of the nasal cavity
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Nerves

• Three major nerves
• CN I, V1, V2
• Vestibule is the most sensitive
• Infraorbital and anterior ethmoidal nerves
• Nasal mucosa supplied primarily by V2
• Anterior by V1 lateral nasal anterior ethmoidal
• Small part for alveolar

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Nerve summery
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Blood Supply to Nasal Cavity
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Arterial and Venous supply

• Blood supplied from both internal and external
  carotid arteries
• Anterior and posterior ethmoidal come off the
  ophthalmic artery (from internal carotid)
• Maxillary branches off the external carotid
• Facial originates from external carotid
• Venous plexus of the lateral wall and septum
• Venous plexuses are important for heat exchange
• Plexuses can dilate and constrict controlling the
  aperture of the nasal meatus
• Venous pathways are roughly the same as the
  arteries
• Drainage occurs into the sphenopalatine, facial,
  or ophthalmic veins
• Ultimately the pharyngeal or pterygoid plexuses

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Epistaxis

• Anterior nasal septum is the Kiesselbach area
• Plexus of all five arteries supplying the septum
• Epistaxis nose bleed
• Generally minor nose bleeds are from arterial of
  venous plexus
• Spurting of blood likely larger artery
  (e.g.sphenopalitine)

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Blood Summery
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Sinuses

• Sinuses are air filled spaces extensions of the
  respiratory epithelium
• They are named for the bones that they are in
  Frontal, Ethmoidal, Maxillary, Sphenoid.
• They serve to expand the surface area of the
  epithelium to increase heat exchange and aid in
  humidifying air
• They produce mucus which must drain into the
  nasal cavity through various openings to the
  nasal cavity.
• Because they are continuous with the nasal cavity
  infections in the nasal cavity often spread to
  the sinuses.
• Because of the small openings of the sinuses
  often times the they can become obstructed during
  infections.

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Nasal Sinuses

• Sinuses continue to develop into adulthood
• Each grows in size taking over more of the bone
• Generally stops or decreases in speed around
  puberty
• Frontal
• Rarely symmetrical
• Innervated by supraorbital nerve (V1)
• Ethmoidal
• 20-24 individual cells
• Innervated by anterior and posterior ethmoidal
  nerves (V1)
• Sphenoid
• Derived from posterior ethmoidal sinus cells
• Develops after age of 2
• Innervated by posterior ethmoidal nerve
• Maxillary
• Largest sinus
• Innervated by alveolar nerves

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Sinus MRI

• Ethmoidal and Maxillary sinuses are obvious

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Sinuses

• Ethmoidal and maxillary sinuses are visible
• Ethmoidal drainage through multiple ducts.
• Anteriorly into the ethmoidal infundibulm which
  leads to the middle meatus
• Middle directly into the middle meatus (are the
  air cells that make up the ethmoidal bulla)
• Posterior drain into the superior meatus
• Maxillary Sinus drains through the maxillary
  ostium through the semilunar hiatus and into the
  middle meatus

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Sinus Drainage
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Sinus Drainage
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Sinus Drainage

• Note how Frontal and Maxillary Sinuses Drain
• Ethmoidal infundibulum leads to the middle meatus
• Semilunar hiatus leads to the middle meatus

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Sinus drainage
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• Rhinitis
• Nasal mucosa becomes inflamed due to infection or
  allergic reaction
• Can be acute or chronic
• Sinusitis
• Sinus mucosa becomes inflamed due to infection
  generally for nasal cavity
• Nasal Polyps
• Noncancerous outgrowths of respiratory mucosa
  that can block airflow
• Deviated Septum
• Septal cartilage is deviated from the midline

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Development