Embryology and Anatomy of Nose and Paranasal Sinuses with X rays Nose and PNS

1. ANATOMY OF NOSE AND
PARANASAL SINUSES
-DR. ALKA KAPIL

2. EMBRYOLOGY OF NOSE AND PNS
The nasal cavity is first recognisable in the 4th
intrauterine week as olfactory or nasal
placode,a thickening of ectoderm above
stomatodeum
This placode sinks to form olfactory pit lying
between the proliferating mesoderm of
medial and lateral nasal folds of frontonasal
process
This deepens to form the nasal sac by 5th
week
Frontonasal process
MP
LNP MNP

3. Maxillary process of the 1st branchial
arch grows to fuse with median nasal fold
and the frontonasal process forming the
primitive nasal cavity
The primitive nasal cavity and the
mouth are seperated by a bucconasal
membrane
The bucconasal membrane thins out
and breaks down eventually forming the
primitive choana

5.  The external nose is thus established with the fusion of five processes :
–– Frontonasal process- bridge of the nose
–– Fused medial nasal processes -dorsum n tip of nose
–– Lateral nasal processes -alae of the nose,
nasal bones n cartilages
–– elevations on lateral wall- chonchae
 Primitive septum
-derived from frontonasal process
-initially entirely of cartilage
-superior part then ossifies to form perpendicular plate of ethmoid,
posteroinferior part-vomer
-anteroinferior non ossified -quadrilateral cartilagenous plate
 Primitive Palate
fusion of maxillary and frontonasal process

6. Palatal processes (d/f lateral maxillary mesoderm) grows medially
fuses horizontally forming the palate and uvula
fusion continues from AP separating the nasal and oral cavities
midline dehiscence  future site of incisive canal

7. Anamolies of development of
nose
Atresia of the nasal cavity or choana
Absence of cribriform plate
Absence of nasal septum
Absence of palate

8. MAXILLARY SINUS
• First sinus to appear
• a shallow groove expanding from primitive
ethmoidal infundibulum into the mass of
maxilla later forming a small cavity
• Pneumatization completes by 12th year of life
Final size reached in 17th to 18th year of life
• First Radiologic Evidence-4-5months after birth

9. Maxillary hypoplasia
enlargement
of the
vertical orbit
lateral position
of the infraorbital
neurovascular
canal
elevated
canine
fossa,
Enlargement of superior
orbital fissure
enlargement of
pterygopalatine
fissure

10. ETHMOID SINUS
During 8th week of IUL,6-7 folds with grooves appear in lateral wall
The folds fuse to form 3-4 crests (aka ethmoturbinals)
1st crest remnant - anterior ascending portion agger nasi
-posterior descending portion uncinate process
2nd crestbulla lamellabulla ethmoidalis
Main fold-supreme,superior and middle turbinates
Most inferior fold(aka maxilloturbinal)-inferior turbinate
Furrows between each ethmoturbinals forms respective meatus
 First Radiological Evidence of the sinus-6years

11. SPHENOID SINUS
• Recognisable at 3rd month of IUL
• Evagination from sphenoethmoidal recess
• Reaches sella tursica by age of 7 years
• Reaches full size between 15years to adult age
• FRE-4 years
FRONTAL SINUS
• From the most AS segment of anterior ethmoid complex
frontal bone
frontalsinus
• Complete development by age of 20 years
• FRE-6years

12. Anatomy of external nose
External nose-pyramidal structure made up of bones n cartilages ,covered by skin
 Root of nose-upper angle of nose which is continuous
with forehead
 Base of nose-triangular;directed downward
with 2 openings- nostrils
 Tip of nose- free angle of the nose below
 Dorsum- connect tip to root
 Bridge- upper bony part of the dorsum
 Columella-?membranous part forming caudal end of nasal septum

13. Nasal skin
 The skin over the -
nasal bones n upper lateral cartilages-thin n freely mobile
alar cartilages-thick n adherent with numerous sebaceous glands
 hypertrophy of these sebaceous glands gives rise to a lobulated tumour called
rhinophyma
 Subcutaneous tissue of the nose is made up of four layers:
1) Superficial fatty layer- directly connected to the dermis
2) Fibromuscular layer- comprises the nasal SMAS(subcutaneous
musculoaponeurotic system)
3) Deep fatty layer- lies deep to the SMAS and contains neurovascular system
4) Periosteum and perichondrium-deepest layer
 During external approach rhinoplasty, dissection deep to the third layer
minimizes post-operative scarring and retraction as the neurovascular
and SMAS structures are preserved

14. Nasal musculature
 Nasal elevators -procerus
- levator labi superioris alaeque nasi
-anomalous nasi muscles
 Depressors -alar nasalis
-depressor septi nasi
 Compressor -transverse nasalis
-compressor narium minor
 Dilator-dilator naris anterior muscle

15. Skeletal framework of external
nose
BONY PART-upper 1/3rd
 paired nasal bone
 paired frontal process of
maxilla
 nasal process of frontal bone
CARTILAGINOUS PART-lower 2/3rd
of nose
 paired upper lateral cartilage-
lower free edge of it is seen
intranasally as limen
vestibuli/nasal valve
 paired lower lateral
cartilage(alar cartilage)
 groove between the upper
and lower lateral cartilages is
known as the limen nasi,
which is the site of
intercartilaginous incisions
 sesamoid cartilage- between
upper & lower lateral cartilage
PYRIFORM
APERTURE
 bounded below and laterally by
the maxilla
 above by the nasal bones
All connected by continuous periosteum n perichondrium

16. BONY AND CARTILAGINOUS FRAMEWORK OF NOSE
COTTLE’S
KEYSTONE AREA
WEAK TRIANGLE
NASION -nasofrontal suture line

17. Framework of nasal cavity
Each nasal cavity-5-7cm length,5cm height,1.5cm at floor n 1-2mm at roof,formed by:
 medial wall
-bony n cartilaginous nasal septum
-membranous columella
 lateral wall
-nasal bone
-frontal process of maxilla
-lacrimal bone
-inferior,middle & superior concha
-p.plate of palatine bone
 Floor
-palatine process of maxilla
-horizontal process of palatine bone
 Roof
-frontonasal part-nasal spine of frontal bone
-ethmoidal part-cribriform plate
-sphenoidal part-body of sphenoid

18. MEDIAL WALL/SEPTUM OF NOSE
 BONY PART
major -perpendicular plate of ethmoid
-vomer
-palatine crest
-maxillary crest
minor -nasal spine of the frontal bone
-rostrum of sphenoid
-anterior nasal spine of the maxila
 CARTILAGINOUS PART
- quadrangular/septal cartilage
- upper & lower lateral cartilage
 sphenoidal process-sourse of cartilage to
harvest during revision rhinoplasty
 Pseudoarthrosis joint reduces risk of # or
dislocation with trauma
 MEMBRANOUS PORTION
- segment of connective tissue
between the caudal portion of the
septal cartilage and columella
pseudoarthrosis

19. Nasal Deformities
deviation of dorsum
to one side

20. ROOF OF NOSE
 formed by cribriform plate & represents olfactory area of the nose
 Boundaries of roof of nose:
laterally - superior turbinate
medially -corresponding part of septum
superiorly - cribriform plate
 It can carry infection intracranially at the time of surgery/ trauma and may
also cause CSF Rhinorrhoea
 Therefore also known as dangerous area of nose
 Olfactory region is lined by brownish epithelium & consists of 3 type of
cells:
1.Olfactory cells - bipolar receptor cells
2.Supporting cells -consisting of microvilli
3.Basal cells - contains yellow pigment
derived from the stem cells,have capability of regeneration

21. -Base of skull is sloping downwards from an anterior to posterior direction
at an angle of 15°
-The olfactory nerves can be seen perforating the cribriform plate
-The frontal sinus is seen between the two tables of the frontal bone
-Anteroinferior to the frontal sinus is the thickened frontal beak
-The pituitary gland lies posterosuperior to the sphenoid sinus
BASE OF SKULL IN ANTERIOR CRANIAL FOSSA

22. LATERAL WALL OF NOSE
 Lateral nasal wall extends from the nasal
vestibule to the posterior choana
 Anteriorly the lateral nasal wall is lined by
skin and has vibrissae known as vestibule
forms a part of dangerous area of face (d/t
retrograde venous drainage )
 Behind the vestibule is a plain structureless
area lined by nasal mucosa called the atrium
 Behind the atrium are the three scrolls
of the inferior, middle and superior
turbinates, overlying the respective meatii

23. INFERIOR turbinate and MEATUS
 Inferior turbinate is composed of inferior concha,which is a separate bone
covered by respiratory epithelium
 Subepithelium contains a rich cavernous venous plexus
 Inferior meatus is that part of lateral wall of the nose
which lies lateral to the inferior turbinate
 It is the largest meatus, extending almost the entire
length of the nasal cavity
 The nasolacrimal duct opens into it at approx.
1cm posterior to its head
The opening of NLD is called Hasner’s valve
which is formed by small folds of mucosa .
 can be endoscopically identified by gentle
massage of the lacrimal sac at the medial canthus
Septal
swell body
INFFERIOR
TURBINATE

24. MIDDLE TURBINATE AND MEATUS
 Middle turbinate is a convoluted structure,part of ethmoid bone
 Covered by respiratory epithelium,submucosa has limited cavernous tissue
 Attachment:
1. The anterior one-third is in the sagittal plane and is attached to the cribriform
plate
2. The middle one-third lies in the coronal plane and is attached to the lamina
papyracea.
 It separates the anterior ethmoidal cells from the posterior ethmoidal
cells(GL)
3. The posterior third lies in the horizontal plane and is attached to the lamina
papyracea and the
perpendicular plate of
palatine bone
Posterior end of MT–SPF(gap in fusion between
Sphenoid,palatine n ethmoid bones)

25. Anatomic variations of middle turbinate
MT may be pneumatized and ballooned up
: CONCHA BULLOSA
superior meatus may pneumatize the
vertical lamella of the MT :
INTERLAMELLAR CELL OF GRUNWALD
a sharp bend laterally instead of its usual
smooth medial curvature:
PARADOXICALLY BENT MT
normally curved MT may curl upon itself
to produce concavity within it:
TURBINATE SINUS

26.  MIDDLE MEATUS receives drainage from
the frontal, maxillary and and anterior
ethmoidal sinuses
 RELATIONSHIP OF STRUCTURES WITHIN
THE MIDDLE MEATUS:
• Most anteriorly is a curved bony ridge-
uncinate process
• Behind this is the well pneumatized and
most constant anterior ethmoidal cell-
bulla ethmoidalis
• Both these structures are separated by a
semilunar groove called the hiatus
semilunaris
• The hiatus semilunaris is two-dimensional
and leads into a three-dimensional space
which is called as infundibulum

27. Minimal inflammation in the osteomeatal area can block off aeration to the sinuses,
leading to infection in them.
This concept is the basis of Messerklinger’s functional endoscopic sinus surgery
whereby the clearance of this area alone may reverse changes in the draining sinuses
OSTEOMEATAL
COMPLEX
- uncinate process,
- bulla ethmoidalis n
-ethmoidal infundibulum
form the key area or the osteomeatal
unit into which the frontal, the
maxillary and anterior ethmoidal
sinuses drain

28.  Ethmoid infundibulum is separated posteriorly from the ground lamella of the middle
turbinate by a recess called the retrobullar recess
 Occasionally the bulla does not extend upto the base of the skull and is separated
from it by the suprabullar recess
 The retrobullar and suprabullar recesses together form a semilunar space above and
behind the bulla called the sinus lateralis of Grunwald
BOUNDARIES OF SINUS LATERALIS
OF GRUNWALD:
Roof - ethmoid fovea
Floor - by the ethmoidal bulla
Posteriorly - by the ground lamella of the MT
Anteriorly - opens into the frontal recess
Laterally - lamina papyracea
Medially- middle turbinate

29. The relations of the maxillary ostium:
 Inferiorly- inferior turbinate
 superiorly- lamina papyracea
(1-2mm) & orbit
 anteriorly – NLD
(0.5cm)
 posteriorly -posterior fontanelle
Occasionally the double layer mucosa of
nose and sinus may be dehiscent to
produce accessory ostia

30. Messerklinger Landmarks
-during endoscopic surgery four main barriers are traversed while
proceeding deeper in operative field
Ant. Wall of
Bulla
Ethmoidalis
Uncinate
process
Ground lamella of
MT
Ant. Wall of
Sphenoid

31. SUPERIOR TURBINATE AND MEATUS
posterior and superior to middle turbinate
ST - important landmark to identify ostium of
sphenoid sinus which lies medial to it
SM-drains Posterior ethmoid cells
 Supreme Turbinate - occasionally present

32. BLOOD SUPPLY OF LATERAL WALL OF NOSE
 sphenopalatine foramen-Lies
just inferior to the horizontal
attachment of MT
 crista ethmoidalis -small crest of
the perpendicular plate of the
palatine bone(ethmoid crest)
located anterior to sphenopalatine
foramen-
Variations in branching-for
successful endoscopic
ligation of the sphenopalatine
artery for epistaxis
Landmarks to identify SPA during
endoscopic dissection:
Clipped via transnasal
approach
External approach via
modified lynch
incision

33. Blood supply of the nasal septum
Posterior septal artery
PSA –basis of the
nasoseptal mucosal flap for
endoscopic skull base
reconstruction
Incisive canal
Caudal septum n
columella

34. LYMPHATIC DRAINAGE OF NOSE
External nose & anterior part of nasal cavity
Submandibular lymph nodes
Rest of nasal cavity
Upper jugular Lymph nodes
 Lymphatics of upper part of nasal cavity
communicate with subarachnoid space along the
olfactory nerve

35. Venous drainage of nose
Sphenopalatine vein via
Facial and ophthalmic vein
Cavernous sinus
Ethmoid veins
Superior saggital sinus
Foramen caecum

36. Nerve supply of nose
blocked by placing
the pledget high up on
the inside of nasal
bones where
the nerve enters
-central filaments of the olfactory
cellscribriform plateolfactory bulb
 Injury to these nerves can
open CSF space leading to
CSF rhinorrhoea/meningitis
 blocked by placing a
pledget of cotton soaked
in anaesthetic solution
near the sphenopalatine
foramen
MEDIAL WALL OF NOSE
(Branch of nasociliary)
V1
Nasopalatine nerve
Anterior superior alveolar
n.(branch of V2)
LATERAL WALL-
POSTERIOR SUPERIOR
LATERAL NASAL N(PPG)
BRANCHES OF
PTERYGOPALATINE
GANGLION

37. Autonomic control
- it maintain congestion & decongestion of the turbinate & regulate
the air flow in nasal cavity
-Sympathetic supply-deep petrosal nerve
-Parasympathetic –greater petrosal
-Deep petrosal nerve join with superficial petrosal nerve to form
Nerve of pterygoid canal ( Vidian Nerve)
 Vidian neurecctomy- in refractory cases of vasomotor rhinitis

38. PARANASAL SINUSES
• paired structures lined by ciliated pseudostratified columnar respiratory
epithelium
• Function:Lightens the skull,add resonance to speech,AIR CONDITIONING
• functional units based on these drainage pathways:
 ANTERIOR FUNCTIONAL UNIT
-maxillary, anterior ethmoid and frontal sinuses
-These sinuses drain into the nose through the osteomatal complex in the
middle meatus.
 POSTERIOR FUNCTIONAL UNIT
- posterior ethmoid sinus
-drains into the nose through the superior meatus.
 SPHENOID FUNCTIONAL UNIT
-sphenoid sinus
-drains through the sphenoethmoid recess located medial and posterior to
the superior turbinate.

39. MAXILLARY SINUS/ANTRUM OF HIGHMORE
 capacity 15 ml;33mm X 35 mm X25 mm
 Pyramidal structure with boundaries:
1) Base/medial wall -in relation to lat wall of nasal cavity
,middle turbinate & inferior turbinate
2)Apex-towards zygomatic process
3)Anterolateral wall -covered by periosteum, soft
tissue & skin of cheek
contain infraorbital foramen n its content
 This site is used in CALDWELL LUC operation
4) Floor - alveolar & palatine process of maxilla and is
situated 1 cm below the level of floor of nose
5)Roof-floor of the orbit; marked by infraorbital canal
containing infraorbital nerve and vessels.
6)Posterior wall -formed by thin plate of bone
related to pterygopalatine fossa posteromedially
attached to pterygoid plate

40. • It occupies the body of sphenoid
• Choncal,Presellar and Sellar type
• 2 cm high, 2 cm deep and 2 cm wide
• The right and left sphenoid sinuses are often
asymmetrical leading to dominance of one sphenoid
• Ostium - opens into sphenoethmoidal recess medial
to the superior or supreme turbinate
1.5 cm from the upper border of choana
• The average distance from the anterior nasal spine to
the ostium is about 7 cm
SPHENOID SINUS

41. Relations of sphenoid sinus
 superior -pituitary gland-posterosuperiorly
used as transsphenoidal hypophysectomy
-optic chiasmata
-olfactory tract
-frontal lobe of the brain
 anteriorly -sphenopalatine foramen
-sphenoidal crest
-nasal cavity
 inferiorly -nasopharynx & choana
-vidian N
 posteriorly - basilar A
-brain stem
 laterally -cavernous sinus & its content
-int carotid A

42. Ethmoid air cells
 Thin wall air cavities in lateral mass of ethmoid bone
 occupy space between upper third of lateral nasal wall n medial wall of orbit
 Anterior Group -
1. Agger nasi cells
2. Ethmoid bulla
3. Supraorbital cells
4. Frontoethmoid cells
5. Haller cells
 Posterior Group -
-lies posterior to the basal lamina of middle concha
- They are 1–7 in number
-open into superior meatus or in the supreme meatus
-sphenoethmoid cell/ Onodi cell : most posterior cell of this group

43. The anterior ethmoidal cells may migrate anterosuperiorly into the frontal
recess to produce different types of frontal cells classified by KUHN and
Wormald as follows:
 Type I : A single frontal ethmoidal cell above agger nasi and below frontal sinus
floor
 Type II : A tier of cells above
the agger nasi
 Type III : FECs that fill <50% of frontal
sinus
 Type IV : FECs that fill >50% of frontal
sinus
 This classification ensures that surgeon’s view of large frontal recess cell lumen
will not be mistaken for true frontal sinus
 De-roofing of frontal cells needed to reach the frontal sinus
Frontal sinus

44. Once a compartment is manipulated,all diseased mucosal cells within
the compartment must be completely dissected out:
I. to remove obstructive phenomenon
II. avoid leaving behind disconnected cell from the surgical cavity
III. prevent mucocele formation
IV. reestablish post-surgical mucociliary function that is free of
recirculation effects
V. enable maximal delivery of topical therapy
The ultimate goal of surgery is the creation of a new functional sinus
cavity

45. Frontal sinus
 situated between the inner and outer tables of frontal bone,
above and deep to the supraorbital margin
 32mmX24mmX16mm
 Drainage is into frontal recess
 Boundaries:
• Anterior wall-skin over the forehead
• Inferior wall- orbit and its contents
• posterior wall - meninges and frontal lobe of the brain

46. FRONTAL RECESS
 BOUNDARIES:
i.anterior wall: agger nasi cell
ii. posterior wall: bulla ethmoidalis
iii.lateral wall: lamina papyracea
iv.medial wall : middle turbinate
v.superiorly : opens into frontal sinus
 Components and contents of the
frontal recess:
- Aggar nasi
- Bulla
- Upper end of attachment of uncinate process (anatomic variation)
 It may be encroached by several anterior ethmoidal cells, which may obstruct frontal
sinus ventilation and drainage leading to sinusitis

47. Occipito-mental /Water’s View
Patient is facing the X-ray plate and
X-rays are passed from occipital area
directing to chin
This view avoids the superimposition
of temporal bones over maxillary
sinuses
nasal cavity, septum,
frontal sinuses, anterior ethmoid
sinuses and sphenoid sinuses (when
mouth is kept open)
XRAYS-NOSEANDPARANASAL
SINUSES

48. Occipito-frontal/Caldwell View
This view focuses mainly on the frontal sinuses
Patient’s forehead and nasal tip are kept in
contact with X-ray film
structures seen are:
1 Frontal sinus
2 Orbit
3 Nasal cavity
5 Maxillary sinus
10 Ethmoid sinuses
11 Petrous bone

49. X-ray Base Skull
(Submento-vertical View)
The neck and head are fully extended
so that vertex faces the film and rays are
passed beneath the mandible
This view shows sphenoid sinus,
ethmoid sinuses, nasopharynx and
posterior wall of maxillary sinus
Lateral view skull
Patient’s head is placed in lateral position
against the film and the rays are directed behind
the outer canthus of eye
This view is useful to show posterior table of
frontal sinus,maxillary sinus, middle and
posterior group of ethmoid sinuses
1. Cranial cavity
2. Frontal sinus
3. Orbit
4. Sphenoid sinus
5. Maxillary sinus
6. Upper jaw
7. Postnasal space
‘White arrow’—posterior wall of maxilla

50. THANK YOU!