Embryology of the noseEmbryology of the nose
The nose develops from frontonasal process whichThe nose develops from frontonasal process which
grows between the primitive forebrain and the roof of thegrows between the primitive forebrain and the roof of the
stomodium and olfactory placodes which is depressed tostomodium and olfactory placodes which is depressed to
form olfactory pits and maxillary process which groesform olfactory pits and maxillary process which groes
ventrally from the dorsal end of the mandibular arch (1ventrally from the dorsal end of the mandibular arch (1stst
visceral arch). The paranasal sinuses as outpouching ofvisceral arch). The paranasal sinuses as outpouching of
the nasal mucous membrane, the began to appear at thethe nasal mucous membrane, the began to appear at the
third to fourth fetal month growing during childhood andthird to fourth fetal month growing during childhood and
fully developed at 20 yrs. of age.fully developed at 20 yrs. of age.
Bony constituentsBony constituents;;
support the upper part of thesupport the upper part of the
external nose and they are:external nose and they are:
Nasal processes ofNasal processes of
the frontal bonesthe frontal bones..
Nasal bones .Nasal bones .
Ascending processesAscending processes
of the maxillaeof the maxillae..
Cartilaginous constituentsCartilaginous constituents ::SupportSupport
the lower part of the external nose.the lower part of the external nose. TheyThey
1.1.Upper lateral cartilages.Upper lateral cartilages.
2. lower nasal cartilages.2. lower nasal cartilages.
3. Quadrilateral cartilages3. Quadrilateral cartilages
of nasal septum.of nasal septum.
4. Alar cartilages.4. Alar cartilages.
The cartilages are connected with each other and withThe cartilages are connected with each other and with
the bones by continuous perichondrium andthe bones by continuous perichondrium and
periosteum .periosteum .
External noseExternal nose
Is pyramidal in shape, itIs pyramidal in shape, it’’s shape iss shape is
maintained by skeletal frame workmaintained by skeletal frame work..
Anterior naresAnterior nares;;
Situated in the base ofSituated in the base of
the nose and openthe nose and open
downwards, they aredownwards, they are
separated by (columellaseparated by (columella(,(,
a strip of skin, connectivea strip of skin, connective
tissue and medial crura oftissue and medial crura of
the lower lateral cartilagethe lower lateral cartilage..
Thin over the upper part of the noseThin over the upper part of the nose
,and thicker over the lower,and thicker over the lower
cartilaginous part ,where it containscartilaginous part ,where it contains
large sebaceous glandslarge sebaceous glands ..
Muscles of external noseMuscles of external nose ::
The nose has a number muscles which in
man has vestigial importance.
Nerve supply: they are all supplied by branches
of facial nerve.
Arterial supply: all supplied by maxillary and
Venous drainage: through facial and ophthlmic
veins they drain to cavernous sinus.
Lymphatic drainage: either follows anterior
facial vein and opens in to submandibular
nodes, or drains to preauricular lymphnodes.
Nasal fossae:Nasal fossae:
** The right and left nasal fossae (cavities)The right and left nasal fossae (cavities)
are separated by the nasal septum.are separated by the nasal septum.
*The nasal fossa includes only that part*The nasal fossa includes only that part
which is lined with mucous membrane.which is lined with mucous membrane.
* Each fossa communicates with:* Each fossa communicates with:
1.1. The paranasal sinuses,The paranasal sinuses, through their Ostia.through their Ostia.
2- The nasopharynx,2- The nasopharynx, through the posteriorthrough the posterior
Boundaries of posterior choana:Boundaries of posterior choana:
Each posterior choana is bounded:Each posterior choana is bounded:
**AboveAbove ::by body of
ala of vomer,
*Below*Below:: by posterior
margin of horizontal
part of palatine bone,
*Laterally*Laterally:: by medial
pterygoid plate of
*Medially*Medially :: by posterior
free margin of vomer.
Boundaries of nasal fossaBoundaries of nasal fossa
1. palatine process of maxilla in the anterior three
2. Horizontal part of palatine bone in posterior one
RoofRoof (very narrow) :
Cribriform plate of ethmoid, Nasal
through which fiberes of frontal
olfactory nerve pass.
MediallyMedially :: there is nasal septum, which lies in or near
the mid line.
The three main constituents are :The three main constituents are :
11--Perpendicular plate of ethmoidPerpendicular plate of ethmoid,,
above and behindabove and behind..
Other bones which contribute to theOther bones which contribute to the
formation of the septum are:formation of the septum are:
spine of maxilla
2-Nasal crests of maxillary
and palatine bones
3-Nasal spine of
4-Rostrum and crest
of sphenoid bone
5-Crests of nasal
Lateral wallLateral wall:: is formed by
1-Medial wall of maxilla.
2-Lateral mass of ethmoid and lacrimal bone.
Other contribution are derived from:
* Ascending process of maxilla (anteriorly).
* Perpendicular part of palatine bone and behind it, medial pterygoid process
of sphenoid posteriorly.
2-Lateral mass of
of palatine bone
process of sphenoid
The main features of lateral wall are:
1. Three turbinates superior, middle, and inferior.
2. Three meatus named after the turbinates. each lies below and
lateral to corresponding turbinate.
3. Spheno-ethmoidal recess lies above the superior turbibates and
receives the ostium of sphenoidal sinus.
4. superior meatus contains the ostia of posterior ethmoidal cells.
5. Middle meatus is the most complex and by far
the most important, because:
1- The ostia of maxillarymaxillary ,, anterior ethmoidalanterior ethmoidal ,, and frontalfrontal sinuses
open into it.
2- The atriumatrium is forward continuation of middle meatus.
3- The agger nasiagger nasi is curved ridge lying above the atrium.
4- The bulla ethmoidals is a smooth rounded mass formed by
anterior ethmoidal cells, the ostia of these cells open on to the
5- The hiatus semilunaris lies below and infront of bulla and leads
forwards in to the infundibulum. it is bounded below by uncinate
process of ethmoid.
* Inferior meatus receive the nasal opening of naso-lacrimal duct.Inferior meatus receive the nasal opening of naso-lacrimal duct.
Superior meatus occupies the posterior third of
Middle meatus occupies the posterior two
The inferior meatus runs the length of the
The olfactory cleft:The olfactory cleft: occupies the area between
the superior turbinate, cribriform plate and the
corresponding area of the septum and it is lined
by specialized olfactory epithelium.
These are air spaces within certain bones of the skull.
Four on each side:
They are lined with a mucous membrane continuous with that of
the corresponding nasal fossa through their ostia.
Humidifying and warming the inspired
Regulation of intranasal pressure.
Increasing surface area for olfaction.
Lightening the skull.
Adding resonant effect to voice.
Contributing to facial growth.
Function of Paranasal SinusesFunction of Paranasal Sinuses
The exact function of PNSs are uncertain but may haveThe exact function of PNSs are uncertain but may have
role inrole in::
*It is the largest of the sinuses,
with an average capacity of
about 15 ml in the adult.
* Is pyramidal in shape and
occupies the body of the
* The base lies medially,
the apex is in the zygomatic
portion of the maxilla.
* Medial wall is the wall
between the sinus and the
* FloorFloor :is formed by the alveolar
process and hard palate:
Œ- In children the floor lies
at, or above, the level of
the floor of the nasal
Œ- In adults it lies about
1.25cm below the floor of
Œ- The roots of several teeth
may project into, or even
perforate, the floor.
The ostia of maxillary sinus:
*Main ostium is situated
high up between the
medial wall and roof of
It opens into the
*Accessory ostia are
behind the main one.
Both main and accessory
ostia are surrounded by
a wide area of mucous
Relations of maxillary sinus:
1*1*Orbit:Orbit: is separated from
the antrum by the thin
roof of the sinus which
contains the infraorbital
2*2*Teeth:Teeth: may produce
elevations in the floor of
the sinus and the number
of related teeth depends
on the size of the antrum.
The second premolar and
first molar are usually
3*3* Middle meatus of nose:Middle meatus of nose:
is related to the upper
part of the antrum.
4*4* Inferior meatus of nose:Inferior meatus of nose:
is separated from the middle
part of its medial wall by bone,
which is usually thick in front
and below,but thinner above and
5*5* maxillary arterymaxillary artery ::
is related to the posterior
wall, where it occupies the
It may be approached
through the antrum for
6*6* Maxillary division ofMaxillary division of
the Vth cranial nerve:the Vth cranial nerve:
also traverses the pterygo-
7*7* Nasolacrimal duct:Nasolacrimal duct:
medial to the antrum,
to open into the inferior
Ethmoidal sinuses (labyrinths)
*Consist of a number (approximately 7-15) thin-walled
cavities within the lateral masses of the ethmoid bones,
and sometimes in the agger nasi and middle turbinate.
*The cells may invade any of the surrounding bones,
including the frontal, sphenoid and maxillary bones.
There are two groups of cells:There are two groups of cells:
1-Anterior. Usually small and numerous. They open into the
upper part of the hiatus semilunaris or on to it, or above
the bulla ethmoidalis. So Secretions drain into the middle
2-Posterior. Usually large and few. They open into the
*Should be regarded as an
upward extension of an
anterior ethmoidal cell.
*It occupies a very variable
extent of the frontal bone
and may be partly loculated.
*Its average capacity is about
7 ml in the adult.
* The right and left sinuses
are often asymmetrical.
*They are separated by a thin
bony septum, which may be
deficient in part.
* The sinus may invade the
orbital plate of the frontal
bone and occasionally it
extends to the optic foramen.
The frontonasal duct:
*It passes through the anterior
part of the ethmoidal labyrinth.
* Its length and curvature vary
* Its lower end (ostium) usually
opens in to the infundibulum,
less often independently above
Relations of frontal sinuses:
Anterior cranial fossa:
separated from the sinus by
the compact bone of its
Orbit: lies below the floor of
the sinus. This is also compact
bone which may rarely be
Skin and periosteum of forehead:
cover the anterior wall, which is
of diploic bone and is related
To supratrochlear and
*Lies behind the upper part
of the nasal fossa.
* It occupies the body, and
sometimes the wings and
pterygoid processes, of the
* The average capacity is
about 7 ml in the adult.
* The right and left sinuses
are rarely symmetrical.
* They are separated by a
septum which may be
deficient in part and is
The ostium of sphenoid sinus:
*situated in the upper part of
the anterior wall of the sinus.
*It communicates with the
superior meatus indirectly
through the sphenoethmoidal
*Above the sinus there are:
frontal lobe of brain
Mucous membrane of nose and paranasal sinuses:
The mucous membrane of the nose is of two types:
1. Respiratory mucosa:
*This lines the lower two-thirds
of the nasal septum, the lateral
wall of the nose below the
superior turbinate and the floor
of the nasal fossa.
*It is pink in colour and is covered
by a ciliated, columnar epithelium.
*It also extends into the sinuses,
through their Ostia, and is thinner
*It is also continuous with the
epithelia of the naso-lacrimal duct
and Eustachian tube.
Blood supply of nose and paranasal sinuses :Blood supply of nose and paranasal sinuses :
Arterial supply:Arterial supply:
The nasal fossae and paranasal sinuses are supplied by branches
of the external and internal carotid arteries:
A. Derivatives of external carotid artery:A. Derivatives of external carotid artery:
1-Sphenopalatine artery1-Sphenopalatine artery:
via the maxillary artery supplies
the turbinates and meatus of
the nose and most of the septum.
22--Greater palatine arteryGreater palatine artery::
a branch of the maxillary
artery contributes branches
to the lateral nasal wall and
)via the incisive canal) to
the anterior part of the
3-Superior labial artery3-Superior labial artery::
*A branch of the facial artery.
It sends branches to the tip
of the septum and the alae
*Its anastomosis with
a branch of the spheno-
palatine artery and the
greater palatine artery
(`the artery of epistaxis')
plexus, in Little's area.
4-Infraorbital and superior dental arteries:4-Infraorbital and superior dental arteries:
*branches of the maxillary
*They supply the maxillary
5-Pharyngeal branch of5-Pharyngeal branch of
maxillary artery:maxillary artery:
supplies the sphenoidal sinus.
B. Branches of internal carotid artery:
Anterior and posterior ethmoidal arteries:Anterior and posterior ethmoidal arteries:
*branches of the ophthalmic
* They supply the roof of the
nose, anterior parts of the
septum and lateral wall of the
nose, and the ethmoidal and
*Bleeding from these vessels
is seen above the level of the
Venous drainage:Venous drainage:
The veins form a cavernous plexus beneath the mucous membrane
They open into:They open into:
1-Sphenopalatine vein and anterior facial vein, from the plexus.
2-Ophthalmic veins, from the ethmoidal veins.
3-Veins on the orbital surface of the frontal lobe of the brain,
the foramina in the cribriform plate.
4-Superior sagittal sinus, through the foramen caecum.
Vascular arrangements of mucous membrane:
*Arterioles: lie in the deeper part of the subepithelial connective
tissue. They are arranged in longitudinal rows.
lie in networks under the
epithelium and around the
receive blood from the
* Venous plexuses:
also lie in the deeper part of
the subepithelial connective
They drain the sinusoids.
* Venules: collect blood from
Nerve supply of nose:
Nerves of common sensation are derived from:
1. Branches of the Vth cranial nerve:1. Branches of the Vth cranial nerve:
*Anterior ethmoidal nerveAnterior ethmoidal nerve:
A branch of ophthalmic
It enters the nasal
cavity through the
foramen and divides
which supplies the
anterior part of the
which supplies the
anterior part of the
lateral wall of the nose,
and the anterior
parts of the middle
and and inferior
Lymphatic drainage of noseLymphatic drainage of nose
and paranasal sinuses:and paranasal sinuses:
The lymphatic vessels arise from a
continuous network in the
part of the mucous membrane.
Subimandibular lymph nodes:Subimandibular lymph nodes:
collect lymph from the external
nose and anterior part of the
Upper deep cervical nodes:Upper deep cervical nodes:
drain the rest of the nasal cavity,
either directly or through the
Physiology of the NosePhysiology of the Nose
Generally the nose serves the demand for 9 functions:Generally the nose serves the demand for 9 functions:
Respiration: the nose is the primary passage for theRespiration: the nose is the primary passage for the
inspiratory air current in a continuous stream over theinspiratory air current in a continuous stream over the
inferior and middle turbinate where it’s divided byinferior and middle turbinate where it’s divided by
anterior ends of these turbinates into two streams aboveanterior ends of these turbinates into two streams above
and below each turbinate to increase the contact surfaceand below each turbinate to increase the contact surface
with the mucosa for better conditioning of the inspired airwith the mucosa for better conditioning of the inspired air
to the lungs, considering that eddie’s stream which mayto the lungs, considering that eddie’s stream which may
happen for a reason or another is not ideal for airhappen for a reason or another is not ideal for air
passage and it may form obstruction to the subsequentpassage and it may form obstruction to the subsequent
current behind it.current behind it.
Purification of the inspired air: where the large particles are detectedPurification of the inspired air: where the large particles are detected
by the vibrassies of the nasal vestibule and the smaller particles areby the vibrassies of the nasal vestibule and the smaller particles are
dealt with by lysosomal enzymes, macrophages, and the antibodiesdealt with by lysosomal enzymes, macrophages, and the antibodies
in the mucosal blankets of the nasal fossa.in the mucosal blankets of the nasal fossa.
Humidification and warming of the inspired air: a function which isHumidification and warming of the inspired air: a function which is
carried out by the submucosal venous plexus of sinusides and lakescarried out by the submucosal venous plexus of sinusides and lakes
of the inferior and middle turbinates by transduction of the heat toof the inferior and middle turbinates by transduction of the heat to
the cold inspiratory air and from the air to the sinusides of the hotthe cold inspiratory air and from the air to the sinusides of the hot
Olfaction: which is carried out by the superior part of the nasal fossaOlfaction: which is carried out by the superior part of the nasal fossa
in the olfactory area where the odours of nearly 30 oderant typesin the olfactory area where the odours of nearly 30 oderant types
are carried by the olfactory nerve ending across the olfactoryare carried by the olfactory nerve ending across the olfactory
filament to the olfactory bulb where it’s perceived as an odour afilament to the olfactory bulb where it’s perceived as an odour a
sense which is intimately related to taste (agusia) sense .sense which is intimately related to taste (agusia) sense .
The nose forms a part of the buttress function of the facial skeletonThe nose forms a part of the buttress function of the facial skeleton
where it may receive the first impact of an assault to the nose.where it may receive the first impact of an assault to the nose.
Cosmoses of the nose: the nose occupying the middle part of theCosmoses of the nose: the nose occupying the middle part of the
face, gives the main feature of cosmoses to the face making it oneface, gives the main feature of cosmoses to the face making it one
of the main part of the body where plastic surgery most frequentlyof the main part of the body where plastic surgery most frequently
carried on.carried on. 5151
Adding tone to the speech: the voice is produced by voice boxAdding tone to the speech: the voice is produced by voice box
larynx and it’s formulated into a meaningful speech bylarynx and it’s formulated into a meaningful speech by
supralaryngeal vocal apparatus of pharyngeal, palatal, lingual,supralaryngeal vocal apparatus of pharyngeal, palatal, lingual,
and lip muscles. Main tone of this spoken speech is added byand lip muscles. Main tone of this spoken speech is added by
the nose.the nose.
Lightening of the facial skeleton over the neck: the nose andLightening of the facial skeleton over the neck: the nose and
the paranasal sinuses by the virtue of their pneumotizationthe paranasal sinuses by the virtue of their pneumotization
lightens the facial bone weight over the neck.lightens the facial bone weight over the neck.
Nasal cycle: this is the function of alternate opening andNasal cycle: this is the function of alternate opening and
obstruction of one nasal fossa in turn with the other lasting forobstruction of one nasal fossa in turn with the other lasting for
3-8 hrs. (mainly 4 hrs.), this function is carried by the3-8 hrs. (mainly 4 hrs.), this function is carried by the
autonomic nervous supply to the nose where by sympatheticautonomic nervous supply to the nose where by sympathetic
overactivity with parasympathetic underactivity produceoveractivity with parasympathetic underactivity produce
venous engorgement of turbinal submucosal venous plexusvenous engorgement of turbinal submucosal venous plexus
of sinusides and lakes and consequently turbinalof sinusides and lakes and consequently turbinal
engorgement causing obstruction of the lower nasal fossa andengorgement causing obstruction of the lower nasal fossa and
an opposite event in the upper nasal fossa causing wideningan opposite event in the upper nasal fossa causing widening
and consequently opening of that fossa.and consequently opening of that fossa.