Nasal cavityNasal cavity

• Extends from nares as far back as Extends from nares as far back as posterior nasal apertures or posterior nasal apertures or CHOANAE.CHOANAE.

• Between posterior border of medial Between posterior border of medial pterygoid plates of spehnoid n pterygoid plates of spehnoid n vomer.vomer.

• Here nasal cavity communicates with Here nasal cavity communicates with nasopharynx.nasopharynx.

Lateral wallLateral wall

• Mainly formed by maxilla.Mainly formed by maxilla.

• Perpendicular plate of palatine bone does so Perpendicular plate of palatine bone does so posteriorly n beyond this medial pterygoid posteriorly n beyond this medial pterygoid plate with which articulates.plate with which articulates.

• Extends as far back as choanae.Extends as far back as choanae.

• Sphenopalatine foramen present at the top Sphenopalatine foramen present at the top of perpendicular plate .of perpendicular plate .

• Provides a portal for communication between Provides a portal for communication between nasal cavity n pterygopalatine fossa.nasal cavity n pterygopalatine fossa.

The labyrinth

• Lateral mass) of ethmoid bone.• Occupies much of upper part of maxillary hiatus.• The inferior concha lies below it.• Articulating anteriorly with maxilla n post: with

palatine bone.• Superior n middle conchae are part of ethmoidal

labyrinth.• These conchae called also as turbinates=are

curved shelves of bone projects into nasal cavity from their attachments on lateral wall.

• Each enloses a passage the Meatus under its concave inferior surface.

• The Atrium= A depression in front of middle concha,leads upwards into meatus behind it.

• Atrium bounded anterioly n above by ridge=THE AGAR NASI.

• This may contain few ethmoidal air cells.

Anteriosuperior part of lateral wall

• Formed by nasal bone n frontal process of maxilla.

• Lacrimal bone articulate with later n with inferior concha.

• Enclosing between them canal for nasolacrimal duct.

• Opens into upper part of inferior meatus about 1cm behind anterior end of concha.

Medial wall or nasal septum.

• Consist of bone and cartilage.• The traingular vomer,articulating above with

sphenoid body .• Forms posterior border of septum.• Inferiorly it is slotted into a grooved ridge on

hard palate n extends beyond incisive canal.• Vomer is grooved on each side by nasopalatine

nerves.• Perpendicular plate of ethmoid articulates with

upper margin of vomer but not whole length.

Septal cartilage

• Unossified part of ethmoid’s perpendicular plate forms anterosuperior part of septum.

• Inferiorly slotted into a bony groove at its vomerine n amxillary articlulations.

• Anteriorinferior corner of septum is mobile.

• Formed by medial crura of paired major alar cartilages.

THE FLOOR• Upper surface of hard palate.

• Which forms roof of mouth n comprises the palatal process of maxilla n horizontal plate of palatine bone.

• Either side of septum anteriorly a small opening leads to an incisive canal traversed by nasopalatine nerve n greater palatine artery.

• Central part of roof is cribriform plate of the ethmoid.

Face Bones (Cont.)Face Bones (Cont.)

• Inferior Nasal Conchae (2)Inferior Nasal Conchae (2)– Located on each side of Located on each side of

the nasal septumthe nasal septum– Create turbulence in the Create turbulence in the

inspired airinspired air• To increase epithelial To increase epithelial

surface areasurface area• To warm and humidify To warm and humidify

inhaled airinhaled air

Nasal spine of the frontal bone n nasal bones.

• Present in front sloping downwards.• At the back is sloping anterior aspect of

sphenoid body.• The surface marking of cribriform plate is

horizontal plane on which pupils lie as eyes gase directly forwards.

• Skin of external nose is reflected around naris to line vestibule.

• That Part of nasal caity bounded by the ala.

• Skin here bears stiff hairs.

• The mucocutaneous junction is marked by a cresentic infolding,limen nasi.

• This coincide with upper margin of major alar cartilage.

• Mucous membrane lining the roof n upper part of septum n laterall wall is OLFACTORY EPTITHELIUM.

• Mucous secretion traps particulate matter n ciliary action wafts the mucous film back into nasopharynx.

Watery secretion of serous glands• Evaporates to moisten the inspired air.• Mucous membrane is very vascular with large

venous sinusoids and arteriovenous shunts.• Especially over inferior concha n this helps to

warm the inspired air.• Mecous membrane of nose is adherent to

underlying periosteum or perichondrium of nasasl walls.

• When a submucous resection is perforemed surgically mucoperichondrium n mucoperiosteum are elevated before resection of septal cartilgae and bone.

Sphenoethmoidal recess

• Lies above n behind superior concha. It receives ostium of sphenoidal air sinus.

• THE SUPERIOR CONCHA.

• Is small.it extends posteriorly from its junction with middle concha.

• Its lower edge is free n overlies superior meatus into which drain posterior ethmoidal air cells.

Middle concha• Is midway in size n position between superior n

inferior.• Extends back from its junction with superior

concha.• It overhangs the middle meatus.• Which can be seen only when the concha is

displaced.• Behind the posterior end of middle concha the

mucous membrane is the sphenopalatine foramen.

• Flat area in front of the concha is atrium of nose.

Middle meatus

• Presents a convex bulge beneath concha.• Ethmoidal bulla of ethmoid produced by buldging

of middle ethmoidal air cells.• Open on or above bulla.• A curved two dimensional slit the hiatus

semilunaris is present anteriorly to the bulla.• Between the anterior surface of bulla and

posterior edge of uncinate process( a thin,hook like bony leaflet which projects posteroinferiorly from ethmoidal labyrinth).

Hiatus semilunaris• Leads into ethmoidal infundibulum,• A curved cleft bordered medially by uncinate

process n laterally by orbital plate of ethmoid.• Infundibulum extends upwards n forwards n is

frequently continous with frontonasal recess .• In this frontal sinus often opens.• Anterior ethmoidal cells opens into infundibulum

or frontonasal recess.• Attachment of middle concha,referred by

rhinologists as ground lamella of middle turbinate.

• Considered as to divide ethmoidal air cells into anterior n posterior ethmoidal systems.

Blood supply• Sphenopalatine branch of maxillary artery.• Supplies mucosa over the conchae n

meatuses n also much of septum.• Anastomosis with septal branch of labial

( entering through the nostril) n ascending branch of greater palatine ( entering through incisive canal).

• Forming KISELBACH’S PLEXUS.On lower anterior part of septum.Little’s area).

• A common site for epistaxis.

Anterior n posterior ethmoidal branches.

• Of opthalmic artery enter nose from orbit and supply roof n upper parts of lateral wall n septum.

• Mean while both external n internal carotid artery systems supply the nose.

Venous drainage

• Veins accompany arteries n drain in various directions to the pterygoid plexus,facial vein n ohthalmic veins.

• Rarely 1 percent an emissary vein may traverse foamen caecum in front of cribriform plate n connect nasal veins with superior sagittal sinus.

Lymph drainage

• Lymphatics drain to submandibular,retropharyngeal n deep cervical nodes.

• Nerve supply.• Olfactory ara of roof n upper parts of

lateral walls n septum are supplied by olfactory nerves.

• Vestibular area is supplied by the infraorbital lnerve from face.

The respiratory area of lateal wall nerve supply.

• at front by anterior ethmidial nerve in upper part.• In lwer part by filaments from anterior superior

alveolar nerve.• At the upper back aprt by lateral posterior

spperior nasal branches from pterygopalatine ganglion(through sphenopalatine foramen)

• At lower back part by posterior inferior nasal branches of greater palatine nerve(through foramina in perpendicular plate of ethmoid bone.