Anatomy of nose & paranasal sinuses

1. Anatomy of Nose & Paranasal
Sinuses

2. Vestibule
Examination :-By Lifting the tip of the nose.
Dilated Passage way leading from external nose to
the nasal fossa.
Demarcated by Limen Nasi
Superiorly lined by skin, contains hairs, sebaceous
gland and sweat glands

3. Furunculosis of Nose
Skin loosely attached at the dorsun
and lateral sides but firmly attached
at tip and the Alar cartilage –it
contains sebaceous gland –
Rhinophyma

4. Supporting framework of external
nose
Lower lateral cartilage has horse shoe shape,
lateral cross is broad and strong forms alae,
medial portion is weak and extends partly along
the free caudal end of cartilaginous septum and
partly within the membranous columella.

5. Muscles of the external Nose
Nasal cavity has –medial wall,
lateral wall, roof and floor.
Nasal Septum (Medial wall)
Septum has 3 parts
Bony
Cartilagenous
Membranous (Columella)

6. Lateral Wall
Most important for
FESS
Osteomeatal complex

7. Roof
Upper and lower lateral cartilage.
Nasal bones
Nasal process of frontal bones
body of ethmoid
body of sphenoid
Cribiform plate –Major part of roof.
Transmits the filament of the olfactory nerve, which
distributes in the mucous membrane covering the
upper part of the nose
2-4 cm
2
area

8. Floor
Palatine process of maxilla
Horizontal process of palatine bone

9. Turbinates
Inferior turbinates –largest, separate bones,
bones of the inferior turbinate is deeply pitted,
cellular, surface of the turbinate is perforated by
blood vessels.
(Turbinectomy -Turbinoplasty)

10. Inferior Meatus
–Nasolacrimal duct (Hasner's Valve)
Middle turbinate
Smaller then inferior turbinate
Stroma of the middle turbinate contains many
gland
Key structure in FESS

11. Variations of middle turbinate
Concha bullosa
Paradoxical MT
Double Middle turbinate
Polypoidal change in MT

12. Middle Meatus
Osteomeatal complex
All the anterior group of sinuses (Maxillary,
anterior ethmoid, frontal sinus) drains.
Deep crescentric groove hidden by the MT is
infundibulum
Fissure leading from MT into infundibulum is
hiatus semilunaris
Ethmoidal bulla –bulge from anterior ethmoid
cells.

13. Superior turbinate–not visualized by anterior
rhinoscopy or nasal endoscopy.
Smallest of all the turbinates
Landmark for the ostium of sphenoid sinus

14. Superior Meatus
Posterior ethmoid drains
Supreme turbinate occasionally present
Sphenoethmoidal recess –above and behind the
superior turbinate –sphenoid sinus opens

15. Functional Anatomy
Respiration
Olfaction
Paranasal sinuses
Frontal Sinuses
Ethmoid Sinuses
Maxillary Sinuses
Sphenoid Sinuses

16. Maxillary Sinus (Antrumof
Highmore)
Largests of all the sinuses
Presence since birth
At birth floor of maxillary sinuses is above
the nasal floor, descends continuously until
it reaches the age of 8 yrs –Same level

17. At the age of 18yrs floor of maxillary sinus
is below the floor of nasal cavity.
Shape-Pyramidal, base towards the nasal
cavity, apex towards the zygoma.
Natural osteum of maxillary sinus opens in
middle meatus.
Anti-gravity drainage, cilliary movement is
towards the natural osteum in middle
meatus.
Inferior meatal anstrostomy –non
physiological

18. Relation
Roof –floor of orbit –infraorbital nerve
Blow out # -entrapment of inferior rectus
muscles
Medial wall –lateral wall of nose
Anterolateral wall –bone undernith cheek
Posterior wall –separates its from pterygo
palatine fosa.
Floor –upper alveolus and hard palate
2
nd
premolar and 1
st
& 2
nd
molar in relation
with maxillary antrum
Chronic Maxillary Sinusitis
Removal of the teeth –Oroantral fistula

19. Sphenoid Sinus
Small before 3yrs but fully develop by 12 –15
yrs.
Situated within the sphenoid bone, variable in
size and shape
Separated from each other by bony septum.
Communicates with superior meatus by small
aperture which opens into spheno ethmoidal
rescess. Size varies –0.5 –4 mm
Anti-gravity drainage

20. Relation
Anteriorly –posterior ethmoid cells
Posteriorly–Posterior cranial fossa
Superiorly–Anterior and middle cranial fossa
Optic chiasma anteriorly and pituitary fossa
posteriorly.
ICA, optic nerve and cavernous sinus laterally
Pituitory fossa –transnasal / transsphenoidal
hypophysectomy

21. Ethmoid Sinus
Ethmoid cells lies in either side just lateral to the
superior 1 half of the nasal cavity medial to bony
orbit. Ethmoid bones have horizontal plates and
vertical plates that are at right angle with each other.
Vertical portion has superior part called crista galli and
inferior part called perpendicular plate of ethmoid.
The horizontal plate is comprised of medial portion –
cribiform plate and lateral portion that forms the roof
of ethmoid.

22. Contd…..
Two groups of ethmoid air cells
anterior group
Posterior group
Separated by basal laella
Anterior group drains to middle
meatus
Posterior group drains to superior
meatus
Clinically–attachment of middle
turbinate to lateral nasal wall marks the
line of division between anterior and
posterior group

23. Anterior group lies infront and posterior
group lies above and behind
The two group differ in size, usually the
posterior ethmoidal cells are fewer in
number 3-7 and larger in size.
Contd…..

24. Mucoele in children
It is relatively well developed at
birth.
It has a close relation with orbit
(Lamina papyracea) and
anterior cranial fossa, infection
may spread easily to these
structure.
During FESS in inexperience
hand there is a chance of injury
to these area.

25. Frontal Sinus
Absent at birth, rudimentary till the age of 7
yrs.
Rarely identical, varies greatly in size and
shape.
Bony septa may divide sinus into one or
more compartment.
Occasionally it may not phenumatize at all.
It drains to middle meatus through fronto-
nasal duct.
The duct is tortuous bony passage runs
through the anterior ethmoid sinus down to
middle meatus.

26. Contd…..
It is because of its tortuosity
and length the duct gets block
to form frontal mucoele.
Frontal sinus has anterior
table, posterior table (which
also forms the roof) and floor
Relation –posteriorly –frontal
lobe
Inferiorly –roof of ethmoid
medially and roof of orbit
laterally.
Inferiorly in the floor the
fronto-nasal duct, its anterior
wall forms the bony forehead.

27. Nasal Mucus membrane
Nasal cavity, nasopharynx and sinuses are
lined by pseudo stratified columnar ciliated
epithelium (Respiratory type)
The vestibula area of nasal cavity is lined
by cuboidal epithelium
Area above the superior turbinate is lined
by olfactory epithelim –it is brownish in
color, confined to cribiform plate, it extends
medially to septum and laterally to superior
turbinate. Olfactory nerve may get damage
by head injury –loss of smell (anosmia)
Nasal polyp –hyposmia of anosmia

28. Nerve supply
Nose and paranasal sinuses has
Sensory
autonomic
specific sensory (olfactory)
Sensory: Through the ophthalmic and
maxillary division 5
th
nerve
Autonomic:the secretory gland of the nasal
mucosa are under the control of autonomic
nervous system via the nerve of pterygoid
canal (vidian nerve), which contains both
sympathetic fibres and para sympathetic
fibres.

29. Contd……
Sympathetic stimulation constrict the mucosal
vessel, reduces the size of turbinate –
enlarging airway. Parasympathetic stimulation
reverse the condition.
Olfactory nerve fibre
The bipolar olfactory cells that lies in the
olfactory epithelium are the first order of
neurons. Axons from these combined to form
about 20 olfactory nerves.
These nerves pass through the cribiform plate
to relay at the olfactory bulb.
The neurons from the bulb run in the olfactory
tract to the 2
nd
olfactory centre in the frontal
lobe. The cortical olfactory centre is in the

30. Blood Supply of Nasal cavity
Recurrent posterior epistaxis –
sphenopalatine artery ligation.
Venous drainage –
Venous drainage of nose and paranasal
sinuses is to the ophthalmic vein, facial vein
and to the pterygoid and pharyngeal plexus.
Cavernous sinus thrombophlebitis

31. Lymphatic drainage
The anterior part of the nose and the sinuses
drains to submandibular lymphnode and to
deep cervical chain.
Posterior part of nose and posterior sinuses
drain to retropharyngeal lymph node.
Functions of paranasal sinuses
air conditioning
pressure damping
reduction of skull weight
heat insulation
increase the olfactory area
vocal resonance
mucus production
Diseases in the sinus from the nasal cavity of