Dentist in pune.(BDS. MDS) - Dr. Amit T. Suryawanshi. Nose & Paranasal sinuses.

SURGICAL ANATOMY OF
NOSE& PARANASAL
SINUSES.
Dr. Amit T. Suryawanshi
Dentist & Oral and Maxillofacial Surgeon
Pune, India
Contact details :
Email ID - amitsuryawanshi999@gmail.com
Mobile No - 9405622455

CONTENTS
• INTRODUCTION
• EMBRYOLOGY OF NOSE & PARANASAL SINUSES
• ANATOMY OF NOSE & NASAL CAVITY
• FUNCTIONS OF PARANASAL SINUSES
• PARANASAL SINUSES
- EMBRYOLOGY
- ANATOMICAL RELATIONS.
- NEUROVASCULAR SUPPLY.
• CONCLUSION

INTRODUCTION
• The nose & nasal cavities are a complex arrangement
of hard & soft tissues.
• The complexity of the paranasal sinuses anatomy as well
as their many functions make them an interesting topic to
study.
• It is imperative for the surgeon to know the anatomy of
the nose and associated paranasal sinuses,
so as to deal with the disorders involving them.

EMBRYOLOGY
• Developmentally nose and paranasal sinuses are interlinked.
• The frontonasal process inferiorly differentiates into two
projections known as “Nasal Placodes”. These structures
later fuse to become the nasal cavity and primitive choana,
separated from the stomodeum by the oronasal membrane.
• The primitive choana forms the point of development of
posterior pharyngeal wall and the various paranasal sinuses.

Nasal placodes-
These structure fuses to
form the nasal cavity and
primitive choana.
Choana – forms the point
of development of posterior
pharyngeal wall and
paranasal sinuses.
The oronasal
membrane - It gives rise
to the floor of the nose and
palate

 The frontonasal prominence gives rise to inferior
mesodermic projection which goes on to form the nasal
septum dividing the nose into two cavities.
• The skeletal system develops from mesoderm.

• At about 25 – 28 weeks of gestation, three medially directed
projections arise from the lateral wall of the nose.
• This serves as the beginning of the development of
paranasal sinuses.
• Between these projections small lateral diverticula
invaginate to eventually form the meati of the nose.

The medial projections arising from the lateral wall of the nose
forms the following structures:
• The anterior projection forms the agger nasi
• The inferior projection forms the inferior turbinate and
maxillary sinus
• The superior projection forms the superior turbinate, middle
turbinate, ethmoidal air cells and their corresponding
drainage channels.
• The middle meatus develops between the inferior and
middle turbinate.

• The middle meatus
invaginates laterally to
form the embryonic
infundibulum and
uncinate process.

Nose
• Nose – part of upper respiratory tract.
• Two halves of nasal cavity opens into the face through the
nares.
• Nares continues posteriorly as nasopharynx through
posterior nasal aperture.

•The NOSE consists two parts:
- internal part
- external part.
•The internal part is much larger than the external part.
•The external nose is the part that projects from the face.

Skeleton of external nose
Framework is composed of bone and fibroelastic cartilages.
Bony framework supports – upper part of nose .
It comprises of following bones:
- nasal bones
- frontal process of maxilla
- nasal process of frontal bone.
- vomer bone
- bony septum.
- perpendicular plate of ethmoid bone.

DIAGRAM SHOWING BONES FORMING SKELETON OF
EXTERNAL NOSE

Cartilaginous frame work consists of :
1) median quadrilateral septal cartilage
2) paired upper lateral cartilage
3) major and minor alar nasal cartilage

Cartilagenous skeleton of the external nose
Septal cartilage –
• Quadrilateral in side view
• Antero-inferior part of
nasal septum is devoid of
cartilage & membranous
septum continues with
columnella.

Lateral nasal cartilage
• Triangular in shape.
• Ant. margin is more thicker than
posterior margin.
• Superior margin attach to nasal
bone & frontal process of
maxilla.
• Inferior margin connected to
major alar cartilage by fibrous
tissue.

Major alar cartilage-
• Thin flexible plate lying
below upper lateral cartilage.
• Curves acutely around ant.
part of naris.
• It narrows posteriorly & is
connected to frontal process
of maxilla by fibrous
membrane containing 3-4
minor alar cartilages.

DIAGRAM SHOWING THE ALAR CARTILAGE

Skin of external nose-
• Skin covering external nose in the upper portion is thin and
loosely connected to underlying structures.
• Over apex and alae is thicker and more adherent which
bears numerous large sebaceous glands having distinct
orifices.

Arterial supply of skin – septal branches of facial artery
- dorsal nasal branches of ophthalmic
artery
- infraorbital branches of maxillary
artery.
Venous drainage of skin into
- facial vein
- ophthalmic vein.

Nerve supply:
- motor branches to the nasal muscles:
buccal branch of the facial nerve.
- sensory branches to the skin:
- ophthalmic nerve
- infratroclear & external nasal branches of
nasociliary nerve.
- nasal branches of the maxillary nerve.

• The entire nasal cavity
extends from the nares
(nostrils) anteriorly to
the choanae posteriorly
Choanae
• It is divided into 2
parts by an
osseocartilaginous nasal
septum

NASAL CAVITY
Each half of the nasal cavity has a:
• Floor
• Roof
• Lateral wall
• Septal wall

Functions of the nasal cavity :
• It forms the superior part of the respiratory tract
• A passageway for air to lungs
• Filters impurities, especially dust from inspired air
• Warms and humidifies inspired air

• Organ of smell
• Aids in phonation
• Receives secretions from paranasal sinuses
• Receives secretions from nasolacrimal duct

The Floor
- Smooth, concave transverse
and slopes up from anterior to
posterior aperture.
- It constitutes upper surface of
hard palate.
Palatine process
maxilla
Horizontal plate
palatine bone

•Anteriorly, near the septum a small infundibular opening
in the nasal floor leads to incisive canals that descend to the
incisive fossa opening.
• It is marked by slight depression in the mucosa.

The Roof
• Narrow
• Formed by a number of bones and cartilages
Nasal Cartilages, Nasal, Frontal, Ethmoid,Sphenoid Bones
http://www.netterimages.com/images/vpv/000/000/000/986-0550x0350.jpg

• Anterior slope is formed by nasal spine of the frontal and
nasal bones which contributes to external nose.
• Central horizontal region is formed by cribriform plate of
ethmoid bone which separates the nasal cavity from floor
of anterior Cranial fossa.
• The posterior Slope is formed by the body of sphenoid
bone – interrupted on each side by opening of sphenoidal
sinus.

The medial wall (Nasal Septum)
- Divides the nasal cavity
into right and left halves
-It is partly osseous and
partly cartilaginous
-Bony part is formed by
vomer bone & perpendicular
plate of ethmoid bone.
Perpendicul
ar Plate
(ethmoid)
Vomer
Septal
Cartilage

•The antero-inferior part of the nasal septum contains
anastomosis between
a) superior labial branch of facial artery &
b)sphenopalatine branch of maxillary artery.
•This is called as little’s area or kisselbach’s area.
•It is a common site of bleeding from nose(epistaxis).

The Lateral Wall
Marked by 3 projections:
- Superior concha
- Middle concha
- Inferior concha
Inferolateral to each concha there lies a corresponding
passage called as meatus.

•Above the superior concha the triangular spheno-ethmoidal
recess bears the opening of sphenoidal sinus.
•Sometimes a 4th concha , the highest nasal concha
appears on the lateral wall of this recess.
•The passage immediately beneath it is termed as
supreme nasal meatus.
•Bounds most of the paranasal sinus and receives
opening from these sinuses.

• The middle meatus has two parts :
– frontal recess
– the descending ramus
• The descending ramus is marked by the ethmoid bulla, the
uncinate process and the semilunar hiatus
• Sometimes there is a complete absence of drainage of
maxillary sinus due to adherence between ethmoid bulla and
uncinate process

DIAGRAM SHOWING PARTS OF MIDDLE
MEATUS

Agger nasi cell:
• The cell is found in the lacrimal bone anterior and
superior to the junction of the middle turbinate with the
nasal wall (often described as the bulge in the lateral
nasal wall where the middle turbinate attaches).
• It is hidden behind the anterior most aspect of the
uncinate process and drains into the hiatus semilunaris.

Agger nasi cell and ethmoidal bulla

• It is the first cell to pneumatize in the newborn and is
prominent through childhood.

Diagram showing openings of sinuses in lateral wall of nose.

Openings in the nasal cavity:
• Superior meatus : -posterior ethmoidal sinus
• Middle meatus : - maxillary sinus
- frontal sinus
- anterior & middle ethmoidal sinus
• Inferior meatus : nasolacrimal duct
• Sphenoethmoidal recess : sphenoidal sinus.

OPENING OF SINUSES IN THE LATERAL WALL OF
NOSE

• Arterial supply:
- anterior & posterior ethmoidal branches of
ophthalmic artery.
- sphenopalatine branch of maxillary artery.
- labial branch of facial artery.
-
• Venous drainage:
- sphenopalatine vein
- facial vein
- ophthalmic vein

Lymphatic drainage:
• Lymph vessels from Anterior Region of nasal cavity pass
superficially to external nasal skin – ends in
submandibular lymph nodes.
• Rest of nasal cavity, paranasal sinuses, nasopharynx all
drains to upper deep cervical nodes,through
retropharyngeal lymph nodes.
• The posterior Nasal floor probably drains to the parotid
nodes.

Nerve supply:
- anterior ethmoidal branch of nasociliary nerve
- infraorbital nerve
- anterior superior alveolar nerve
- posterior superior nasal nerve
- nerve of pterygoid canal.
- olfactory nerve.

DIAGRAM SHOWING NERVE SUPPLY OF LATERAL
WALL OF NOSE.

PARANASAL SINUSES
•Paranasal sinuses are the mucosa lined air spaces
present within the bones of the face & skull.
•These sinuses are present in the bones of same
name.

There are four bilaterally paired paranasal
sinuses-
- Frontal sinus
- Maxillary sinus
- Ethmoidal sinus
- Sphenoidal sinus

DIAGRAM SHOWING PARANASAL SINUSES

•All sinuses opens into lateral wall of nasal cavity by small
aperture that allow the equilibrium of air and movement of
mucus.
•Position of aperture , form and size of sinus vary
enormously between individual.
•Mucosa of sinus is continuous with nasal cavity – which
favours spread of infection.

• Mucous is secreted by glands and swept through
there aperture into the nose by there cilia.
• The mucociliary escalators is the normal mechanism
for clearing sinuses and maintaining aeration.

FUNCTIONS OF PARANASAL SINUSES
• Humidifying and warming the inspired Air.
• Imparts resonance to voice
• Increases surface area for absorption of noxious gases
and trapping of particles in inspired air
• Lightens the skull

•Helps in absorbing the shock of blows to the face &
thereby limiting the extent of facial injury from trauma.
•Serves as an accessory olfactory organ by evenly
distributing the inspired air.

MAXILLARY SINUS
• Largest of all the paranasal sinuses.
• Also known as the “antrum cave of Highmore”– English
physician described an infection of sinus in 1651.
• First sinus to develop.

• 3rd IU month - mucosal outpouching of the ethmoidal
infundibulum (primary pneumatization – confined to
mucosa of nasal capsule)
• 5th IU month – secondary pneumatization occurs,
growth into adjacent maxilla.
•At birth - it shows a small ovoid groove in maxilla &
close to the orbit.

•At 9 years – 60 % adult size, becomes tubular in shape.
•12 years- Antral floor parallels to nasal floor.
•15-18 years- Adult size, pyramidal in shape.

DIAGRAM SHOWING GROWTH OF MAXILLAY
SINUS

-Sinus growth correspond to eruption of permanent teeth.
-Sinus enlarges by bone resorption at all the walls except
the medial where deposition is accompanied by resorption
at the nasal cavity thus expanding the nasal cavity

DIAGRAM SHOWING CORONAL CUT SECTION
OF FACE

The dimensions of maxillary sinus are:
At adulthood:
3.2-3.4 cm Anteroposterior (depth)
3.0-3.5 cm ( vertical height)
2.3-2.5 cm (width)
-with a volume of approximately15-20 mL.

According to the shape, maxillary sinus is classified as
under:
1-Semi-ellipsoid (15%)
2-Paraboloid (30%)
3-Hyperbolic (47%)
4-Cone-shaped(8%)

ANATOMY OF MAXILLARY SINUS
The maxillary sinus has a horizontal pyramidal shape that consists of :
- base
- an apex
- four sides i.e - a) Superior wall
b) Anterolateralwall
c) Posterolateralwall
d) Inferior wall.

BASE OF SINUS:
-the base of maxillary sinus is formed by lateral wall of nose.

APEX OF THE SINUS:
- It is formed by junction of the maxillary bone & the
zygomatic bone.
- On an average the distance between base and the apex
measures around 25mm.
- Sometimes,when the sinus is large the apex extends into
the zygoma.

MAXILLARY SINUS(SAGITTAL SECTION)

SUPERIOR WALL:
- This wall forms both- roof of sinus & floor of the
orbit.
• It is thinnest wall & mostly flat slopes slightly
anteriorly and laterally.
• The Infraorbital canal runs along this wall and crosses
from back to front- accentuates the fragility of wall.

•This wall is frequently involved in orbital and maxillary
trauma.
•Because of the relative thinness of this wall position of
the Infraorbital Tumors of maxillary sinus can erode this
wall readily.

ANTERO-LATERAL WALL :
•Anterior aspect of the maxilla extents from :
- piriform aperture medially to the zygomatico-maxillary
suture laterally
- superiorly infraorbital rim ,to alveolar process and
maxillary teeth inferiorly.
•Convex towards sinus. Thickness is 2-5mm.Thinnest portion
over canine fossa .

•From the outer surface of this wall passes the facial
artery & the facial vein.
•Labial Levator muscles & inferior portion of orbicularis
oculi is attached to this wall above the infra-orbital
foramen.
• These attachments direct the spread of infection from
maxillary teeth.

• This wall also contains the Anterior & middle superior
alveolar nerves.
• Any surgical procedure through this wall may jeopardise
the nerve supply to these teeth.

POSTEROLATERAL / INFRATEMPORAL WALL
• This wall is made up of zygomatic bone & greater wing of
sphenoid bone.
• Separates maxillary sinus from infratemporal and
pterygopalatine fossae.
• This wall is convex, bulging out posteriorly.

POSTERO-LATERAL WALL OF MAXILLARY
SINUS

• Posterior superior alveolar nerves and vessels sometimes
present in close contact with the sinus mucosa.
•In such instances , acute sinusitis is accompanied by pain in
multiple maxillary posterior teeth.
•Immediately posterior to this wall, vital structures include:
-maxillary nerve & maxillary artery
- nerve of pterygoid canal
- sphenopalatine ganglion.

• Access to the pterygopalatine fossa is accomplished
by careful removal of this wall.

FLOOR OF THE SINUS
• The floor of sinus is formed by maxillary alveolar process.
• It is approximately1.5 cm below the floor of nasal cavity.
• It corresponds to the line drawn laterally from ala of the
nose.
• Descending order of proximity to sinus-, 2nd molar, 1st molar,
3rd molar, 2nd Premolar, 1st Premolar, canine.

•Septa may be present in the alveolar recess of the sinus -
between the 2nd premolar and 1st molar.
•Bone may be dehisced exposing the roots to the sinus
mucosa - periapical & sinus pathology may be
indistinguishable from symptoms alone.
•Risk of creating oroantral fistula increases with age.

DIAGRAM SHOWING GROWTH OF MAXILLARY
SINUS

• The ostium :
– Communication between maxillary sinus and nasal
cavity.
– Located 2 cm from the anterior aspect , 2 cm from the
posterior wall and 4 cm from the floor of the sinus.
– Opens into posterior part of the hiatus semilunaris in the
middle meatus.

•It doesn’t opens directly in the nasal cavity but opens
into a narrow ethmoid infundibulam.
•Ostium is occasionally considered as canal of 3 to 5 mm
length ,it is the location of the invagination of the nasal
mucosa in the embryological phase.

PHYSIOLOGY OF MAXILLARY SINUS
• Lined with respiratory epithelium continuous with the nose
and other paranasal sinuses.
• Mucoperiosteal lining: Epithelium (pseudostratified ciliated
columnar epithelium) + lamina propria + periosteum
(intimately attached) Schneiderian membrane
• Numerous mucus secreting goblet cells.
• Sinus drainage by mucociliary mechanism– mucociliary
blanket – particulate matter from sinus towards ostium -
nasal cavity - nasopharynx

• Spiral movements - 1000 strokes/min – flow rate of 6
mm/min
• Ciliary function may hampered by inflammation,
dehydration, injury, tobacco smoking.

NEUROVASCULAR SUPPLY
Arterial supply:
- Facial artery
- Infraorbital artery
- Greater palatine artery.
Venous drainage:
- by the facial vein
- infraorbital vein
- greater palatine vein.

Lymphatic Drainage :-
Into the Submandibular Lymph nodes.
Nerve supply :
-Infraorbital nerve
-Anterior , Middle & Posterior superior
alveolar nerves.

FRONTAL SINUS
• The frontal sinuses are rudimentary or absent at birth.
• They are developed between 7th & 8th year of life but
reach the full size only after puberty.
• More prominent in males.

• Paired frontal sinuses situated posterior to the superciliary
arches lies between the outer and inner tables of frontal
bone.
• Each underlies a triangular area on surface .
• The inner table is much thinner than the outer table.
• As a result the chances of fracture of the inner table are
more frequent ,even without the fracture of outer table.

The angles of frontal sinus are formed by:
- nasion
- a point 3cm above the nasion
- junction of medial third & lateral two third of
supraorbital margin.

• Average dimensions are –
- Vertical height - 3.2 cm,
- transverse breadth- 2.6cm,
- Anteroposterior depth- 1.8cm.
• Each extends upward above the medial part of the
eye brow and back into medial part of roof of orbit

•The aperture of each sinus opens into the anterior part of
the corresponding middle meatus of nose.
•It opens by the ethmoidal infundibulum or through the
frontonasal duct.

Arterial supply:
- supraorbital artery
- anterior ethmoidal artery
Venous drainage:
- into the anastomotic vein in the supraorbital notch
connecting the supraorbital & superior ophthalmic
veins.

Lymphatic drainage:
- into submandibular nodes.
Nerve supply:
- supraorbital nerve.

Variations in frontal sinus:
•Two sinuses are rarely symmetrical the septum between
them usually deviating from median plane.
•The frontal sinus is sometimes divided into a number of
communicating recess by incomplete bony septa.
•Rarely one or both sinuses may be absent, may be racial
differences also can be seen.

•The part extending superiorly in the frontal bone may
small than part extending in supraorbital region.
•Some times one sinus may overlap in front of the other.
•Sinus may extend posteriorly, as far as the lesser wing of
sphenoid bone but may not invade it.

ETHMOIDAL SINUS-
• These are small, thin walled cavities in the ethmoidal
labyrinth.
• These sinuses are small at the time of birth.
• They grow rapidly between 6-8 years of life & after
puberty.

It is formed by following bones-
- Frontal
- Maxillary
- Lacrimal
- Sphenoid
- Palatine

BASE OF SKULL SHOWING ETHMODAL SINUS

• They lie between the upper part of the nasal cavity
and the orbit.
• Separated from the orbit by paper-thin orbital plate of
ethmoid .
• Ethmoidal sinus is of 3 groups
- Anterior group
- Middle group
- Posterior group

Anterior group-
• Also called as the infundibular sinus.
• They lie in the agger nasi and also encroach on the
frontal sinus.
• These are 11 in numbers and open into the ethmoidal
infundibulam or in the frontonasal duct.

DIAGRAM SHOWING ETHMOIDAL SINUS
(SAGITTAL SECTION) -

Middle group-
• Also called as a Bullar Sinus.
• They are 3 in number and open in the middle meatus
by one or more orifices on or above the ethmoidal
bulla.

ETHMOIDAL BULLA:
• This is the most constant landmark for surgery. It lies
above the infundibulum and it's lateral/inferior surface
and the superior edge of the uncinate process forms the
hiatus semilunaris.
• The anterior ethmoid artery usually decends across the
roof of this cell.

DIAGRAM SHOWING ETHMOIDAL BULLA.

Posterior group-
• It lies very close to the optic canal and the optic
nerve.
• These are 1-7 in number and open into superior
meatus.
• Also one or more opens in the sphenoidal sinus.

NEUROVASCULAR SUPPLY –
• Arterial Supply-
- Sphenopalatine artery.
-Anterior and posterior ethmoidal
-arteries
• Venous drainage-
- into the corresponding veins

• Lymphatic drainage-
- Anterior and middle groups drain in the
submandibular nodes .
- Posterior group drains into
retropharyngeal nodes.
• Nerve Supply-
- Anterior and posterior ethmoidal nerves
- Orbital branches of pterygopalatine
ganglion.

Sphenoidal Sinus
• These are paired sinus .
• At birth, the sinuses are minute cavities and
their main development occurs after puberty.
• These are present posterior to the upper part of the
nasal cavity within the body of the sphenoid bone.

Relations :
i)Superiorly– optic chiasma & pituitary gland.
ii)Inferiorly– roof of pharynx
iii)On either side – cavernous sinus & internal carotid
artery
iv) Anteriorly – sphenoethmoidal recess
v) Posteriorly – Pons & medulla

• Average diameter :
- Vertical height - 2cm
- Transverse breadth- 1.8 cm
- Anteroposterior depth- 2.1 cm

Diagram of base of skull showing ethmoidal & sphenoidal
sinuses

Variations in the Sphenoidal Sinus
• They are rarely symmetrical , one often being larger
and extending across the median plane
• One or both may approach closely to optic canal
and partly encircle it .
• If exceptionally large, they extend into the roots of
pterygoid processes and may invade into the basilar
part of the occipital bone.

• The aperture of each sphenoidal sinus opens into the
corresponding spheno-ethmoidal recess high in its
anterior wall.

Neurovascular Supply –
Arterial Supply-
- Posterior ethmoidal artery.
Venous drainage-
- into the ethmoidal vein.

Lymphatic drainage-
- Into the retropharyngeal lymphnodes
Nerve supply-
- posterior ethmoidal nerves
- Orbital branches of pterygopalatine
ganglion.

CONCLUSION
•It is imperative for the oral & maxillofacial surgeon to know
the anatomy of the nose and associated paranasal sinuses ,So
as to deal with the disorders involving them & to preserve the
vital structures.

REFERENCES
• Grays anatomy,39th edition
• Oral and maxillofacial surgery clinics of north
america vol 11 no 1 feb 1999.
• Oral and maxillofacial surgery – Fonseca
• Oral surgery vol 1- Daniel laskin
• Atlas of anatomy- Patrick tank, Thomas gest.
• Netter’s atlas of anatomy.

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Dentist in pune.(BDS. MDS) - Dr. Amit T. Suryawanshi. Nose & Paranasal sinuses.

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