endoscopic anatomy of nasal cavity
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Transcript of endoscopic anatomy of nasal cavity
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,ðmoid 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
E BOSS 18-08-2011
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
E BOSS 18-08-2011
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
E BOSS 18-08-2011
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
E BOSS 18-08-2011
-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
E BOSS 18-08-2011
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
E BOSS 18-08-2011
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
E BOSS 18-08-2011
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