SURGICAL ANATOMY OF

NOSE & PARANASAL

SINUSES.

Dr. Amit T. Suryawanshi

Dentist & Oral and Maxillofacial Surgeon

Pune, India

Contact details :Email ID - amitsuryawanshi999@gmail.comMobile 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 posteriorlyChoanae

• 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

http://www.netterimages.com/images/vpv/000/000/000/986-0550x0350.jpg

Nasal Cartilages, Nasal, Frontal, Ethmoid,Sphenoid Bones

• 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.

LATERAL WALL OF NOSE

• 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.

DIAGRAM SHOWING PARANASAL SINUSES

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) Anterolateral wall

c) Posterolateral wall

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.

DIAGRAM SHOWING OSTIUM

•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.

DIAGRAM SHOWING PARANASAL SINUSES

• 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.

DIAGRAM SHOWING FRONTAL SINUS

• 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.

Sphenoidal sinus

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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