ENDOSCOPIC ANATOMY OF NOSE, PNS AND ANTERIOR BASE OF SKULL

ENDOSCOPIC ANATOMY OF NOSE and PNS .

1

DR.RAJAT JAIN

ENDOSCOPIC EVOLUTION

2Endo within ; skopeein to seeOptical device with lightingUsed to look inside a body cavity, organ

Endoscopic anatomy divisonMedial wall-septumLateral wall 3 turbinates- inferior (separate bone) middle superior 3 meatus- superior meatus middle meatus inferior meatus Opening of various sinusRooffloorBlood vessels anterior ethmoidal artery, sphenopalatine artery

4 diagnostic nasal endoscopyA careful and methodical diagnostic endoscopy is the key.

Equipment

Procedure

Normal endoscopic findings

Anatomical variations

1st passThe 0 endoscope ( or 30 ) is passed along the floor of nasal cavity between inferior tubinate and septum.Septum mucosa , spur or deviations.Inferior turbinate.Posterior choana.Posterior wall and roof of nasopharynx.Eustachian tube & fossa of rosenmullar.Inferior meatus nasolacrimal duct opening.

1ST PASS

Boundaries of posterior choanaeanteriorlyandinferiorlyby thehorizontal plateofpalatine bone,superiorly and posteriorly by thesphenoid bonelaterally by themedial pterygoid plates.medially by the Vomer

2nd pass

Scope is passed along the floor upto posterior choana and then moved upward medial to the middle turbinate along the roof of posterior choana.Superior turbinate and meatus.Sphenoethmoidal recess.Sphenoid ostium lies 1- 1.5 cm above the roof of posterior choana.Below ostium at the roof of posterior choana is mesh of blood vessels woodrufs plexus.

2ND PASS

3rd passExamine middle meatus.Gently retracting middle turbinate with freers elevator or advance scope posteriorly and roll the scope under inferior border of the middle turbinate to enter posterior roomy part and withdrawn from posterior to anterior .Uncinate processBulla etmoidalisGroove btw these two hiatus semilunarisPalpated with ballpoint goes into infundibulum.

3RD PASS

NOSE

Development nose 4th to 8th week IUL.

Nose

External noseInternal nose

Nasal septum

Blood supply of nose

Inferior turbinateIndependent bone.

Straight course

Inferior margin overhangs inferior meatus

Inferior meatus having opening of NLD

Middle turbinateProjection from medial surface of ethmoidal infundibulum.

Divided into three parts depending upon attachment and orientation in 3D space.

Anatomical variationsBallooned up concha bullosa .Superior meatus pneumatize vertical lamella interlamellar cell of Gurnwald.Paradoxically bent turbinate.

ANATOMICAL VARIATIONS

Middle meatusLying lateral to middle turbinate.Recives drainage from frontal , maxillary, anterior ethmoidal sinuses.Structures -

Uncinate processBulla ethmoidalisHiatus semilunarisInfundibulumMaxillary ostium

OSTEOMEATA L COMPLEX

Uncinate processAnuncinate processis a hook-shaped projection or protuberance from a bone or organ. Uncinate process of ethmoid bone, a process located in the nasal cavity

ANATOMIC VARIATION OF UNCINATE

Ethmoidal air cellsAnterior group-most prominent- bullae ethmoidalisPosterior groupSeparated by ground lamella

Agger nasi cellPneumatization of lacrimal bone Forms a bulge anterior to the middle turbinate on the lateral wall.

Ethmoidal bulla

Well pneumatized , most constant, anterior ethmoidal cell.Seperated posteriorly from ground lamella by recess retrobullar recess.Seperated from base of skull suprabullar recess.Semilunar space sinus lateralis of Gurnwald.Opens into middle meatus hiatus semilunaris superioris.

HALLER CELLHaller cellsare also known asinfraorbital ethmoidal air cellsormaxilloethmoidal cells.

present in ~20% (range 2-45%) of patients

In most instances they are asymptomatic

Anterior etmoidal artery

Branch of ophthalmic artery it accompanies thenasociliary nerveruns through theethmoidal canalto supply the anterior and middleethmoidal cells,frontal sinus, and anterosuperior aspect of the lateral nasal wall.

Anterior etmoidal arteryWhen entering thecranium, it gives off:a meningeal branch to thedura mater.nasal branches. These descend into thenasal cavitythrough the slit by the side of thecrista galli, and, running along the groove on the inner surface of thenasal bone, supply branches to thelateral wallandseptumof the nose, and a terminal branch which appears on the dorsum of the nose between thenasal boneand thelateral cartilage

Frontal sinusFrontal recessBounded anteriorly agger nasi cell.Posteriorly bulla ethmoidalis.Laterally lamina papyracea.Medially middle turbinate.Superiorly opens via frontal ostium into frontal sinus.

Posterior ethmoids

Located posterior to ground lamellaeBigger in size as compaired to anterior groupVariant-onodi cell

comparison

Posterior ethmoidal artery

Superior tubinate and meatus.Projection from medial surface of ethmoidal infundibulum.Superior to middle turbinate.Superior meatus below superior turbinate.Posterior ethmoidal cells open into it.

Olfactory epitheliumOlfactory area is confined to the following narrow zones of the nasal cavity:1. Upper 1/3 of the lining mucosa of the nasal septum2. Corresponding area of the medial aspect of superior turbinate3. Corresponding area of the narrow roof of the nasal cavityThis portion of mucosa can be readily identified from the rest of the nasal mucosa by its unique yellowish color.

Sphenopalatine artery

Sphenopalatine arterysphenopalatine artery(nasopalatine artery) commonly known as theartery ofepistaxis branch of themaxillary arterywhich passes through thesphenopalatine forameninto the cavity of thenosethe sphenopalatine artery ends on thenasal septumas theposterior septal branches. Here it willanastomosewith the branches of thegreater palatine artery.

SPHENOID SINUSOstium lies high on its anterior wall close to its roof.Drain into sphenoethmoidal recess.Lies 1- 1.5 cm above the roof of posterior choana.10 % posterior ethmoidal cell extend posterolaterally over sphenoid sinus Onodi cell.

Sphenoid sinus

Types of sphenoid sinus pneumatization

Conchal type(3%): In this type the area below the sella is a solid block of bone without an air cavity.This type is common in children under the age of 12 because pneumatization begins only after the age of 12.Presellar type(11%): In this type the air cavity does not penetrate beyond the coronal plane defined by the anterior sellar wallSellar type(85%): In this type the air cavity extends into the body of the sphenoid below the sella and may extend as far posteriorly as the clivus.

Approaches medial to middle turbinateOstium is visualized and anterior wall of sphenoid is punched downward to open sphenoid sinus. intermediate route.

MEDIAL APPROACH

ONODI CELLOnodi cellsThe sphenoethmoidal air cell is generally defined as the posterior mostethmoidal air cell,that extends posteriorly to lie superolateral to thesphenoid sinusand thus in close proximity to theoptic nerveandinternal carotid artery

ONODI CELLIt often extends into the anterior clinoid process; importantly aeration of the anterior clinoid process does not imply presence of an Onodi cell, as frequently such aeration is due to rescesses of the sphenoid sinus9.

Sphenoid septaNever midline(optic 7%, ICA 40%)

Endoscopic Anatomy of sphenoid sinus

Relationshipsuperiorly: cavernous sinus, sella turcica and its contentsinferiorly: nasal cavitiesanteriorly: nasal cavitiesposteriorly: contents of the middle cranial fossa,laterally: cavernous sinus, cranial cavity

Various patterns of internal carotid in sphenoid sinus

Paranasal sinusesAir containing cavities in certain bones of skull.Clinically divided into two groups:- anterior group maxillar sinus, frontal sinus and anterior ethmoidal sinus. posterior group posterior ethmoidal sinuses and sphenoid sinus.

Anterior skull baseFloor :- * orbital roof *fovea ethmoidalis * planum sphenoidale * cribriform plate.

Posterior wall of maxillary sinus

Pterygopalatine fossaanterior: superomedial part of theinfratemporal surfaceofmaxillaposterior: root of thepterygoid processand adjoining anterior surface of thegreater wingofsphenoid bonemedial:perpendicular plateof thepalatine boneand its orbital andsphenoidal processeslateral:pterygomaxillary fissureinferior: part of the floor is formed by thepyramidal processof the palatine bone.

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