DR.ASHOK KUMAR., MS ENT PG,

ENDOSCOPIC NASAL ANATOMY

EMBRIYOLOGY

7th&8th wk lat.wall of nasal capsule begins to form series of ridges of mesenchchymal tissue

1st ridge the Ethmotubinal-INFERIOR TUBINATE

Ramus ascendens-anterior ascending parts Ramus decendens-post,inf,more horizontal

part ET-1-5(maxillo tubinal/nasotubinals) S1-s6 –major furrows

ET1-regress during later development

ET-1 desending portion (UP) ascending portion(aggar nasi) ET1/ET2-bet furrows(ethmoid

infundibulam) ET2-permanent MT ET3-permanent ST Fusion of ET4/ET5-supreme turbinate

Frontal,maxillary,&ethmoid sinus arises from evagination of LNW

sphenoid sinus arises from post. evagination of nasal capsule

Maxillary sinus –develop from ethmoidal infundibulam

HS-from desending portion of 1st primary furrow

SM-develop from S2 Upper most meatus from-S3 BERTINI OSSICLES-unpneumatized sphenoid

Tubinates

Tubinates are ends of the bony lamella

Tubinates has a visible/invisible part(ground lamella)

Passage bet tubinate are meati

GROUND LAMELLA

1ST- uncinate process

2nd- bulla ethmoidalis

3rd- middle tubinate

4th- superior tubinate

5th- supereme turbinate

LATERAL WALL OF NOSE BONES-from before backwards 1.nasal bones 2.frontal pr.of maxilla 3.lacrimal bone 4.sup& middle nasal conchae of ethmoid

labrinth 5.inf. Nasal concha 6.perpendicular plate of palatine

bone(orbital sphenoid pr.) 7.medial pterygoid plate Cartilages-ULC,LLC(alar cartilage) Fibrofatty tissue-covering with skin in lower part

INFERIOR TURBINATE&MEATUS

Largest tubinate and lagest meatus Highest at the jn of mid 1/3rd Separate bone covered by thick mucus

memb. irregular surface with vascular channels

NLD opening in ant portion of lat wall of IM slit like openig protected by fold of mucus

memb.plica lacrimalis or valve of hasner maxillary pr. articulate with inf. marigin of

maxillary hitus

Nasolacrimal duct

Middle tubinate & meatus

Portion of ethmoid bone It receive drainage from the frontal maxillary

&ant.ethmoidal cells MM- Atrium ,aggar nasi,limen nasi, Maxillary hiatus uncinate pr.,bulla ethmoidalis, hiatus semilunaris, ethmoidal infundibulum recess terminalis

Opening –frontal sinus in ethmoidal inf. Through FND,AEC

Superior turbinate &meatus Is approx. ½ length of MT starts from middle of lower turbinate ST-projects from medial surface of

the ethmoidal labyrinth,below &infront of SER

SUPREME TURBINATE u/l or b/l in 60 % of individuals Ostia of PEC opens into supreme

meatus[75%]

Blood supply

Nerve supply

Aggar nasi

Most ant. Part of ethmoid bone Represented by small crest or mound

on the lateral wall just ant. To the attachment middle tubinate

It may be pneumatised [5-80%]

Aggar nasi cell

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Aggar nasi cell

Aggar means- mound/eminence Nasi means-nose Pneumaticed from FR Just above & ant to MT insertion Ant. –frontal pr. Of maxilla Superiorly- FR/FS Anterolaterally –nasal bone Inferomedial-UP Inferolaterally –lacrimal bone

Middle turbinate(3RD LAMELLA) Ethmoid bone(fromET2) Divides into segments- ant1/ 3rd –horizontal

seg.sagittaly oriented attaches to

skull base mid 1/3rd – vertical portion ,

oriended to coronal plane att.to LP

post.1/3rd – inferior horizontal portion

Basal lamella of MT divides ethmoid labrynth into AEC/PEC

Shape of the MT is highly variable[paradoxical MT,CB]

MT attachments-

1.ant-aggar nasi region at crista ethmoidalis(ethmoidal eminence of maxilla)

2.superioriy/medially-vertically lateral aspect of lamina cribrosa(CP)

3.inferiorly – lamina papyracea[medial wall of the MS]

4.most post.aspect of MT-lat wall at crista ethmoidalis of pp of palatine bone just ant to SPF

SBR

RBR

Sinus Lateralis

Middle turbinate: Horizontal and vertical basal lamella

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paradoxical MT CONCHA

BULLOSA]

Uncinate process

Sagittaly oriented after reflecting MT

3 layered structure 3 to 4mm wide,/1.5 to2cm

length Normally

anterosuperiorly attach to ethmoidal crest of maxilla just inf. To lat attach .of MT fuses with post.aspect of lacrimal bone

UP-ATTACHMENTS

Posteroinfriorly attach.to ethmoidal pr. Of IT

Anteromedial boundary of EI

Posterior marigin is free-no bony attach.

Superior attachment -LP

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Superior attachment-MT

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Superior attachment –skull base

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Medialized uncinate[double MT]

uncinate

uncinateuncinate

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LATERALISED UNCINATE [MAXILLARY SINUS HYPOPLASIA]

Ethmiodal bulla Most constant ant.ethmoid air cell Largest anterior ethmoidal cell Anterior to basal lamella of MT Post.to uncinate process Superiorly ant.wall of the BE extend to skull

base Form post. Limit of

the frontal recess Pneumatised ET2 Type-simple,compound, complex

Ethmoidal bulla[anatomical variants]

Highly pneumatised [retrobullar recess,suprabullar recess]

Low lying bulla- potentially narrow ethmoid infundibulam l/t impaire mucocilliary transport

unpneumatised[8%] –torus lateralis[bony projection fron LP]

Hiatus semilunaries

Hiatus means-gap,cleft,passage way Semilumaris means-cresent shaped Sickle shaped[moon ]-2D sagittal ceft Between post.free marigin of UP and

ant. Wall of bulla ethmoidalis Forms the doorway that lead to

ethmoidal infundibulum Inferior HS of grunwald[MI] Superior HS –bet.EB/MT[EI]

Osteomeatal unit

Not discrete anatomic structure

Collectivelly several MM struc.[UP,EI,AEC]

SINUS LATERALIS

When the posterior wall of the BE is not in contact with BL of MT

Suprabullar recess[space sup.to bulla] Retro bullar recess[space behind thhe BE]-forms

lateral sinus of grunwald Sinus lateralis lise P- basal lamella of MT A- roof &posterior wall of BE S - roof ofethmoid L-lamina papyracea

Ethmoidal infundibulum

Cleft like 3D space in lateral wall of nose

Funnel shaped passage Boundaries: Ant.-lacrimal bone Post. –ant.surface of the

ethmoidal bulla Superior –frontal recess Med. -entire extend

of UP &mucosal covering Lat.wall - LP

Ethmoidal infundibulum ends anteriorly in acute angle-v shaped in axial cut

If UP attaches with LP –EI closed superiorly by blind pouch called TERMINAL RECESS

Frontal recess opens medial to EI Posteriorly EI tapers parallel to tappering of UP entire length of EI -4cm Greatest width-approx.5-6mm[free marigin of

UP] Maxillary ostium –mid3rd lower part of EI FND –drain into ant sup.to upper end of EI

Zones of ethmoid box

ZONE A anterior

OMC[anterosuperior attachment of MT to posterolateral att. Of MT]

ZONE B posterior OMC

[posterolat. MT to face of sphenoid sinus ]

ZONE C sphenoid sinus [SS to

neighbouring structure]

ANTERIOR ETHMOIDAL ARTERY

canal for AEA is over superio medial aspect of orbit –pyramidal sign

Anatomy is highly variable

Commonly injured during attempts to asscess frontal sinus outlet tract

Bony covering is very thin

Posterior ethmoidal arteryanterior nasal crest to anterior ethmoidal foramina 22 -24 mm

ant. to post. ethmoidal artery 12 – 15 mmpost.ethmoidal artery to optic canal 3 – 7mmimportance

Hellar cells inferomadial

aspect of the orbital rim

variation-10% Also called - maxilo orbital

cell maxilloethmoidal cell orbitoethoidal cell Infero orbital

ethmoidal cell

Ethmoidal cells

Anterior ethmoidal cell:[6-14/smaller in size] 1.frontal recess cell 2.infundibular cell 3.bullar cells 4.Cochal cell 5.exramural cell[cell outside the ethmoid] -supra orbital cell -aggar nasi cell -haller cell

Posterior ethmoid cell:[1-5/larger insize ]

intramural post. Ethmoid cell extramural post. Ethmoid cell -onodi cell

Post ethmoid sinus Derived from 2nd /3rd primary furrow Boundaries ant –BL of MT post.-anterior wall of SS Lat- LP Medially by –ST/supreme turbinate Superiorly – ethmoid roof Specific sugical signi.-d/t proximity to

skull base/optic N

Poterior ethmoid cells

GL forms the partition bet.AEC/PEC Located post. & sup. To GL No.of cell vary 1 to 5 Drain into the sup & sup .m Can develop lat. & sup to SS dissection always –inferomedial direction

rather then superolateral direction Most vulnerable point jn of rostum with

roof of spenoid

anatomical variation in PEC -onodi 38 variations with PEC/optic

N[12 major group] Distal opening of optic canal: next to the most PEC[50%] at jn of PEC/ant.SS[25%] next to ant. SS [25%]

onodi cell

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Onodi cellsphenoethmoidal cell

Onodi cell supero ethmoidal cell-extend posteriorly along the LP into the ant. Wall of SS

INCIDENCE-9-12% Optic n /med.recti m

lisein close relation with lat. Wall of this cell-vulnerable o injury during sugery

Delano clasification[onodi cell]

Type 1-optic N courseing adj. to SS without intentation of wall,contact with PES

TYPE2-M/C 76% optic N course adj. to SS causing indentation of sinus wall without making contact with PES

TYPE3-optic N course through SS with atleast 50% surreounded by air

Type4-nerve course adj. to SS/PES TY2,3- 77% as with dehiscent 85% of optic N as with pneumaticed ant.clinoid

pr.[ indication of optic n vulnerability during FESS

Frontal recess [frontal infundibulum] FR –funnel shaped narrowing towards

the frontal ostium Boundaries: M- superior attch. Of MT L –LP S –internal os of frontal sinus A –frontal pr. Of maxilla [aggar nasi] P –superior extention of ethmoidal

bulla/skull base

Frontal recess narrowed by Anterior-aggar nasi

cell,frontoethmoidal cell[ty 1,2,3], inter frontal cell

Posterior-superior orbital cell,frontobullar

, suprabullar cell

importance

Considering complexities of FR serial CT scan required to know the exact anatomy

Extensively pneumatised aggar nasi can be mistaken for FR /FS

residual posteroosuperior wall of aggar nasi can scar & iatrogenic stenosis of frontonasl connection can occur

Frontal recess

Lamina papyracea

Frontal beak

FRONTAL SINUS

Theories : direct extention of the FR By end of 2nd yr one ant. Ethmid cell

migrate upward & forms frontal sinus Ethmoid infundibular cell

Suprabullar cell

Supraorbital cell

-Anatomic variation in

FR

AEA

FS

SOC

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-Anatomic variation in FR-commonly occurs from Pneumatisation of orbital plate frontal bone by ethmoid air cell

-Ventilation to FS/SOC-common ostium at FR

Supraorbital cell

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frontobullar cell

From FR/AEC can develop into frontal bone along the side of frontal sius called

“ BULLA FRONTALIS”

Frontal ells[bent& kuhn classification]

Type 1-single frontal recess cell above aggar nasi cell but below FS

Type 2-tier of more then one cell in FR above the aggar nasicell

Type 3-large single cell pneumatised into frontal sinus[<50%hight of FS]

Type 4-single isolated cell in frontal sinus

[>50%hight of the FS]

Type 1 frontal cell

Type 2 frontal cell

Type 3 frontal cell

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Type 4 frontal cell

Interfrontal sinus septal cell [IFSSC]

KEROS CLASSIFICATION

TYPE I TYPE II TYPE III

1to 3mm 4 to 7 mm 8 to 16mm type3-[dangerous type during fess]

Sphenoid sinus

Pneumatize from SER from birth Extensive variation 3 types based on

pneumatisation cochal[fetal]2% presellar[juvenile]10 to 25% sellar [adult] 86% Superior – thin bone base of skull Lat. –optic N ,ICA

Types of sphenoid peumatisation

conchal sellar Post sellar

Berger classificationE BOSS 18-08-2011

ENDOSCOPIC APPEARENCE

ANATOMIC VARIATIONS

variations in course of ICA in relation toSS

result in different pattern of bulgein wall of the sinus

ICA AND SPHENOID

Angle of attack

The more acute the angle Less the chances of Skull base injury

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Stenberg canal

Applied aspect

Optic N extend backwards & disappears towards posterior wall

25% ICA partially dehiscent 6% dehiscent optic N Maxillary nerve may be surrounded

by pneumatisation Canal for vidian N may bulge on floor

of SS

Thank you