Session 3: nose, nasal cavity, and paranasal sinuses

Nasal complex

made up of bones of nasal cavities and paranasal sinuses

Nose

External portion of nasal complex that protrudes outwards from skeletal component

Nasal cavity

Hollow cavity, anterior border is nasal aperture

Paranasal sinuses

4 pairs of cavities in bones around nasal cavity

External view of nose and nasal cavity

ala, nasal septum, nasal aperture

Ala

Lateral margins of nose

Nasal septum

Divided in half, cartilaginous portion

Nasal aperture

pear shape

Internal view of nose and nasal cavity

• nasal septum formed by: vomer, ethmoid bone, fibrocartilaginous septum

  • 3 shelves of nasal conchae: superior, middle, inferior

Superior of nasal cavity

• small holes open to anterior cranial fossa

• cribiform plate of ethmoid bone

• transmits olfactory nerves from nose to brain

Inferior of nasal cavity formed by hard palate

• palatal processes of maxillae

• horizontal portion of palataine bones

Lateral walls

• ethmoid: upper half; two-thirds

• maxillae: lower half; one-third

What does the ethmoid portion of lateral wall form?

superior and middle nasal conchae

What does the maxillae portion form?

Portion of lateral wall

Where does the maxillae and ethmoid meet?

at inferior nasal conchae which separate bone itself

posterior of nasal septum

choanae/posterior nasal aperture; border of nasopharynx

posterior- superior nasal cavity

• composed of body of sphenoid where meets ethmoid

• sphenoethmodial recess

• sphenodial sinus located below pituitary fossa (hypophyseal); most inferior portion of sella turica

What is the respiratory tract lined with?

pseudostratified columnar epithelium with goblet cells aka respiratory epithelium

Cilia

move in synchronized beating pattern toward anterior portion of nasal cavity

Goblet cells

Secrete mucous onto cilia; mucous traps contaminants onto cilia which moves them forward from to be expelled

nasal conchae

increase surface area to allow for more cilia and goblet cells to be present to assist in trapping and expulsion

What does the epithelial lining consist of?

cilia, pseudostratified columnar epithelium, goblet cells, nasal conchae, modified epithelium

What does posterior 2/3 of nasal cavity consist of?

pseudostratified columnar epithelium with goblet cells

modified epithelium on:

• roof of nasal cavity

• upper surface of superior concha

• upper nasal septum

olfactory epithelium

have neve fibers to detect odors

What are the 4 sinuses?

ethmoid, frontal, maxillary, sphenoid me

meatus

opening under each concha

inferior meatus

• beneath inferior concha

• nasolacrimal duct open here

• carries tears from lacrimal gland to nasal cavity

middle meatus

• beneath middle nasal chocha

• hiatus semilunaris: crescent shaped opening

• ethmoid bulla: bulbous ridge above hiatus semiluaris

• location of opening for frontal, maxillary, and anterior ethmoidal sinuses

• various other openings

hiatus semilunaris

crescent shaped opening

ethmoid bulla

bulbous ridge above hiatus semilunaris

superior meatus

• beneath superior nasal chocha

• smallest nasal meatus

What does the paranasal sinuses consist of?

inferior meatus, middle meatus, hiatus semilunaris, ethmoid bulla, superior meatus, inferior meatus

frontal sinuses

• located in frontal bone above orbital cavity

• vary in size

• may cross midline

• drain into anterior of hiatus semilunaris

  infections cause pressure and pain above eye

What happens if there is a infection in the frontal sinuses?

causes pressure and pain above eye

sphenoid sinuses

• located in body of sphenoid under hypophyseal (pituitary) fossa

• cross midline

• open/drain into superior-posterior nasal cavity (sphenoethmodial recess)

• infection cause congested feeling deep in middle of head

What happens when there is an infection of the sphenoid sinuses?

Cause congested feeling deep in middle of head

ethmoid sinuses

• aka ethmoid air cells

• not single-paired sinuses with paranasal sinuses

• numerous small clusters

  • anterior

  • middle

  • posterior

• inflammation can cause pressure and pain around nose and between eyes

what happens when there is inflammation of ethmoid sinuses?

cause pressure and pain around nose and between eyes

anterior ethmoid air cells

• lateral wall of nasal cavity at base of middle nasal concha

• open into hiatus semilunaris posterior-inferior to opening of frontal sinus

middle ethmoid air cells

• at base of middle nasal concha

• behind anterior air cells

• located in ethmoid bulla

• may have openings in hiatus semilunaris and ethmoid bulla

posterior ethmoid air cells

• located at base of superior nasal concha

• open into superior meatus

maxillary sinuses

• largest of paranasal sinuses

• open to posterior end of hiatus semilunaris

• grows drastically through puberty

  • starts out pea-sized

  • later extends from canines to third molars, and floor of orbital cavity to roots of maxillary molars

• have compartmental walls

• usually connected by openings

• opening is 2.3 way up medial wall

  • makes drainage difficult

• mucousal edema during infection may swell opening shut

what happens when there is inflammation of maxillary sinus

causes pain in upper molars

function of sinuses

• lighten bone weight

• flow of air is minimal

dental complications

• same nerve supplies maxillary teeth and maxillary sinuses

• brain used to receiving signals from teeth but not sinuses

• incorrectly interpret sinus pain as tooth pain

• patient may present with tooth pain that is sinus related

• tooth may be normal for all tests

• PA may show cloudiness in sinus (fluid)

• floor of maxillary sinus dips around apex of maxillary posterior teeth

• periapical infection may involve sinuses

• dilacerated roots may pinch sinus and can remove part of sinus floor on extraction, check with x-ray

• maxillary sinus can fill in area when tooth extracted, complicate option of implants

Which bones form nasal septum?

vomer, ethmoid, fibrocartilaginous portion of septum

what is the function of nasal epithelium?

• goblet cells - secrete mucous

• cilia - trap and expel contaminants

• modified epithelium - special nerve fibers to perceive odor

Where is the olfactor epithelium found?

the upper surface of superior concha, upper nasal septum, and roof of nasal cavity

name the paranasal sinuses?

frontal, sphenoid, ethmoid and maxillary

which sinus is the largest?

maxillary