8 Nasal Cavity

8/2/2019 8 Nasal Cavity

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Today we will talk about the nasal cavity and the palate which are the roof

of the oral cavity which Is located between the oral cavity and the cranial

cavity

The nasal cavity is the passage way between the outside environment and thepharynx posteriorly

(The pharynx is a very large structure that divides posteriorly into

1- Behind the nasal cavity, we call it the nasal part of the pharynx

(nasopharynx)

2- Part of the pharynx behind the oral cavity (oropharynx)

3- Behind the larynx called (laryengopharynx)

** So you can see that the pharynx is a large structure relatively speaking tothe larynx

So the nose is the structure that extend anteriorly outside all the way

posteriorly until the nasal part of the pharynx , Its covered by skin from

outside and by mucus membrane from inside ( mucus membrane covering the

inside of the nose is covering by specific type of epithelium called

respiratory epithelium which is psedustratified columnar epithelium

ciliated )

** In order to understand the nasal area we subdivide the nose into 2 parts,

1- The external nose which is the prominent part of the face that you see

2- The cavity within the skull that we refer to it as the nasal cavity (the

major part)

* The external nose

Its made of bony and cartilaginous part, the bony part is more posteriorly

and it is usually formed by:-frontal process of maxilla.

-the nasal bone (2 small plates) on the bridge or the dorsum of the nose

-the nasal process of the frontal bone

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However the more prominent part in the face is made cartilaginously by the

cartilages that we refer to them lateral cartilages ( lateral alar and septal

cartilages )

For more description we call them1- Upper lateral,

2- Lower lateral that are the alar or alar cartilages and those are u shaped

so they are extended from the lateral to the medial part of the nose with 2

crura (2 legs, lateral and medial crus)

3- And there is another smaller group we refer to them lesser alar

* So the alar are two greater one and behind it there is the lesser alar

** we have one in the middle that helps in separating the nasal cavity intotwo spaces right and left nasal cavity so we call it the septal cartilage and

this one in living human is considered as a part of the nasal septum because

it helps in separation the 2 nasal cavities ,,

The nasal septum is formed by 2 bony parts the vertical or perpendicular

plate of ethmoid superiorly and the vomer inferiorly and more anteriorly in

the prominent part in the external nose you will find the cartilage there

which is called septal cartilage ( you can see it in a living human not in a skull

because its cartilaginous )

**The nasal cavity

** It extend from the outer nares (nostrils) (external nares) which are 2

openings from the outside into the nose

** The inner nares ( choanae ) are the openings between the nasal cavity

and the pharynx behind.

So it extend from the external nares to the posterior aspect of choanae (its

demarcate by the end of the conchae, those elevations or shelves on the

lateral walls of the nasal cavity we refer to them as conchae)

So the boundaries

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# IN the medial wall we have the nasal septum.

#IN the lateral wall:

1- We can see anteriorly a depression area; we refer to it as the vestibule(more related to the external nose)

**The vestibule are characterized by covering by a skin so part of the skin

folded back inside into the lateral wall of the nose and thats why you can

see hair follicles and hair growing inside the nose behind the vestibule there

is the conchae.

2- Conchae: a Latin word that means shell (superior, middle and inferior)

they are found in the lateral walls also

And each space covered by each conchae we call it meatus which is a passage

way

Superior meatus covered by superior conchae

Middle meatus covered by middle conchae

Inferior meatus covered by inferior conchae

The posterior wall of the conchae demarcate the end of the nasal cavity so

the posterior part of the conchae is the end of the nose where we find the

choanae (the opening from the nose into the nasopharynx)

# the roof is made of:

1- Part of sphenoid bone.

2- The ciribriform plate of ethmoid bone.

3- The frontal bone and nasal bone.

# the floor is the hard palate (the floor of the nasal cavity is the roof of

the oral cavity)

*the soft palate separating the nasopharynx from the oropharynx

*hard palate is made of palatine process of maxilla bone and horizontal plate

of frontal bone

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** Nasal conchae and Meatus

As I told you the conchae are bony projections that project inferiorly like

shelves.

* Superior conchae and middle conchae comes from ethmoid bone

* Inferior one is a separate bone

Beneath each concha we have a space we call it meatus.

The conchae are there to protect the opening of the paranasal sinuses which

opens into the meatus, not the air sinus!! Whats the difference???

** paranasal sinuses are air sinus that will open into the nose because wehave additional air cell which called mastoid air cells that will open in the

middle ear so the

paranasal sinuses are :

1- ethmoidal air cell ( anterior , middle and posterior)

2- the frontal

3- the sphenoid

4- the maxillary which is the largest one

1- In the superior meatus we will have the opening of posterior ethmoidal air

cells.

2- In the middle we have the middle and anterior air cells, the frontal and

maxillary.

So most of the air sinuses opens in the middle meatus

** The arrangement of ethmoidal air cells is oblique and going in a horizontaland vertical way,

So # the anterior most anterior inferior# the middle more posterior superior

# the posterior is the more posterior and the most superior one

(because its the most superior one)

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4- in inferior meatus there is no air sinus opening into it

** There is another opening that connect the lacrimal sac with the

inferior meatus

lacremal apparatus is containing the lacremal gland that gonna secrete

the tears that will be collected in the medial inferior angle of the orbit in

the lacremal sac when the sac is filled the tears start to drop and

through a duct connecting the orbit with the inferior meatus of the nose

(nosolacrimal duct) so the tears start to fall from the nostrils thats

why when you cry you have a runny nose

* We still have the sphenoid air sinus >>> they open into an angle

between sphenoid and ethmoid bone in a place above the superiorconchae we call it sphenoethmoidal recess ( pocket ) that form because

of the angulation between the sphenoid and ethmoid bone

There is another opening that connect the lacrimal sac, IF YOU

REMEMBER (the lacrimal apparatus is made up of lacrimal glandes &

sacs ,the lacrimal glands secret the tears which will accumulate in the

lacrimal sac in the inferior &medial corner of the orbit , when the

lacrimal sac is filled now , the tears start to drop down outside the eye

and through a duct that is called nasolacrimal duct ,connect the orbit

with the inferior meatus of the nose ,so the tears start to drop down

from the nostrils, that is why when you start to cry, you have a runny

nose .

SO, in the superior meatus


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You gonna be asked about all of these air cells, and you must be able to

distinguish each of them.

Q: posterior ethmoidal air cells open into???

1- sphenoethmoidal recess2-superior meatus

3- inferior meatus

ANSWER


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to pass through it and open into the nose, this opening called the

SPHENOPALATINE FORAMEN.

The sphenopalatine foramen usually located behind the superior and

middle conchae, sometime may located behind the middle concha but most

of the time it is located in the gap (area) between sup & middle conchaeSO , in the lateral wall of the nose there is sphenopalatine foramen allow

the passage of maxillary artery into the nasal cavity , once it enters

there, it is called sphenopalatine artery (which is terminal branch of

maxillary artery) , and here it is starting to provide blood supply to the

lateral wall & the nasal septum posteriorly.

2)Now, the anterior part of the nasal cavity is supplied by septal branch

from superior labial artery which is branch from facial artery.

3)The roof of the nasal cavity ( that separates the cranial cavity from

nasal cavity ) , there is 2 artery coming from there , called :

1- anterior ethmoidal artery 2- posterior ethmoidal artery

both of them come from ophthalmic artery , which is branch from ICA

and it locate within the orbit .

4) The floor of the nasal cavity (which is the hard palate) supplied by

greater palatine artery


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very common area for bleeding ( most of the nasal bleeding

EPISTAXIS take place in this area where all arteries unite).

What are the causes for epistaxis???

there are more than 100 causes , so we will not gonna mention them here ,

but you have to know that , these causes are arranged from very simplecauses like picking up with your nose , or from injury to the artery or vein

, or from trauma


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Note: The smell occurs in the superior part of the nasal cavity.

The general sensation now comes from the trigeminal nerve:

1. Ophthalmic nerve: V1 most anterior part and prominent one

When you touch the tip of the nose, its V1

2. Maxillary nerve: the remaining Middle and Inferior part of the nasal

cavity.

Paranasal sinuses

You can read it by yourself they dont have any thing .

1.sphenoid 2.frontal 3.maxillary 4.ethmoidallargest one is the maxillary ,,

we afraid when we have Sinusitis which may lead and spread to the

Meninges Leading into infection of the meninges (meningitis )

For more details and information please go to the slides and the 3rd

script of the first exam.

Palate :

when we speak about the palate we know that is form the floor of thenasal cavity and the roof of the oral cavity , it made by 2 parts hard and

soft one

* HARD PALATE : containing hard tissue bone

*SOFT PALATE : containing soft tissue muscles

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The epithelium found in the nasalcavity is respiratory epipsudosratified columnar epi except upper region or upper third

just above the sup concha the epiwill become simple columnarolfactory epithelium and containthe ends or receptor of the olfactorynerve fibers .


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The first 3 quadrants of the palate is hard and the remaining is soft

Hard Palate:

Composed of:

-Mucous Membrane: that covers the surfaces

- Palatine aponeurosis FIBROUS sheet which made the fibrous part of

the soft palate which is dens regular connective tissue with epithelial

lining.

Its the key stone of the soft palate expanded tendon of Tensor veli

palatine ( nerve supply V3) In addition there is another muscles that

covered with this mucous membrane together it will become 5 muscles

First one of them the TENSOR VELI PALATINE :

2 from each side come down from the base of the skull all the way to

reach the trigoid hamulus extended part of the medial part of the

trigoid plate of sphenoid bone.

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Hard palate:

consist of the palatine process of maxilla

and horizontal palate of the palatine

Soft palate:

Fibro muscular fold covered with mucosa

& attached to post. Border of Hard palate


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*From the base of the skull there is another muscle that will descend all the

way to this aponuroese if it contract it will elevate the soft palate So we call

it Levator veli palatine

2 muscles above: Anterior: tensor veli palatineposterior: levator veli palatine

2 muscles going below: anterior: Palatoglossus m. from the soft palate to

the tongue posterior: Palatopharyngeus m. from the soft

palate all the way to the pharynx and join the wall of it.

The 5th one uvula: a conical projection from post. Border of soft Palate

if you cut it you will find a mucus membrane surrounded a muscle.

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The function of the hamulus toallow the tensor palatine to go orturn horizontally to make the 2tendons of the muscle in each sidemeet each other ,, because thetensor palatine come verticallyfrom the base of the skull .

when this muscle contract thetendons tense and forming thefoundation of the soft palateplalatine aponeurosis : formd bythe 2 tendons of the tensor velipalatinethe teigoid hamulus found only inthe medial teigoid plateno one in the lateral cus its attachto the 2 muscles of mastication(lateral and medial. terigoid


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Palatoglossus m and the Palatopharyngeus m Important clinically Why?!

they are mucus membrane covered and this membrane form a folds when it

each them so they are demarcating the tonsilar bed where dose the

palatine tonsils found,, if you dont see them in the mouth of the patient that

is Healthy state but if they have any enlargement in size that will betonsillitis

Arterial blood supply to the palate :

1. Greater palatine artery for the hard palate

2. Lesser palatine artery for the soft palate

both of them come from the descending palatine artery which come from

the Maxillary artery and pass from the greater and lesser palatine foramens

*Additional Arteries*

1. From the ECA ,, Ascending pharyngeal artery when it go to the pharynx

2.From Facial artery ,, first branch Ascending palatine artery from superior

Palatine Innervation :

1. Greater palatine nerve : hard palate

2. Lesser palate nerve : soft palate

3.nasopalatine nerve : Incisive nerve supply the primary palate which is the

first part formed of the palate found behind the anterior teeth and have a

folds ,,

There is another important area in the palate Vibrating Line : important of

the prosthodontics in the upper teeth , its the border between the movable

and non-movable part of the soft palate

the palate is fibro muscular the tendons part is fixed area when you open

your mouth and say ahhhhhh you see the vibration in the soft palate as

the muscle contract but in the first 2mm in the soft palate we have palatine

aponurouses, it is non-movable but the muscular one is movable, so the

vibration line is the junction between the movable and non-movable parts ofthe soft palate.

Posterior edge of the upper denature must be in the non-movable part of the

soft palate because it depend on the negative pressure.

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Done by: Heba Radaideh, Haya Momani & Sondos Harbeih.

Edited by: C.W.T

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8 Nasal Cavity