Nose, Nasal cavity Nose, Nasal cavity & &

Paranasal SinusesParanasal Sinuses

NoseNose Only externally visible part Only externally visible part

of the respiratory systemof the respiratory system Has a free Has a free tiptip and is and is

attached to the forehead attached to the forehead by the by the rootroot or the or the bridgebridge

Has two openings, the Has two openings, the anterior (external) nares anterior (external) nares oror nostrilsnostrils, , which lead to the which lead to the nasal cavitynasal cavity

Each nostril is bounded Each nostril is bounded laterally by the laterally by the alaala and and medially by the medially by the nasal nasal septumseptum

root

tip

external naresseptum

ala

Nose: StructureNose: Structure Nose consists of Nose consists of bony bony & &

cartilaginouscartilaginous framework framework Formed Formed aboveabove by the: by the:

• Nasal bonesNasal bones• Frontal processes of Frontal processes of

maxillaemaxillae• Nasal part of frontal Nasal part of frontal

bonebone Formed Formed belowbelow by by plates plates

of of hyaline cartilagehyaline cartilage, , which include which include upperupper & & lowerlower nasal cartilages nasal cartilages and the and the septal septal cartilagecartilage

Nasal part of Frontal bone

Nasal CavityNasal Cavity Extends from the Extends from the

external (anterior) external (anterior) nares nares to the to the posterior posterior nares (choanae)nares (choanae)

Divided into right & Divided into right & left halves by the left halves by the nasal septumnasal septum

Each half has a:Each half has a: FloorFloor RoofRoof Lateral wallLateral wall Medial wall Medial wall

(septum)(septum)

RoofRoof Is narrow & formed (from Is narrow & formed (from

behind forward) by the: behind forward) by the: • Body of sphenoidBody of sphenoid• Cribriform plate of Cribriform plate of

ethmoid boneethmoid bone• Frontal boneFrontal bone• Nasal bone & cartilageNasal bone & cartilage

FloorFloor

• Separates it from the Separates it from the oral cavity oral cavity

• Formed by the Formed by the hard hard (bony) palate(bony) palate

Medial Wall (Nasal Medial Wall (Nasal Septum)Septum)

OsteocartilaginousOsteocartilaginous partition, only rarely partition, only rarely lying in the midlinelying in the midline

Covered by the Covered by the mucoperiosteummucoperiosteum

Formed:Formed:• SuperiorlySuperiorly by the by the

vertical vertical (perpendicular) plate (perpendicular) plate of ethmoid boneof ethmoid bone

• PosteriorlyPosteriorly by the by the vomervomer bonebone

• AnteriorlyAnteriorly by the by the septal cartilageseptal cartilage

Lateral WallLateral Wall Shows three horizontal Shows three horizontal

bony projections, bony projections, covered by mucous covered by mucous membrane, the membrane, the superiorsuperior,, middlemiddle && inferiorinferior conchae (turbinates)conchae (turbinates)

The The superior and middle superior and middle conchae are parts of the conchae are parts of the ethmoid boneethmoid bone, whereas , whereas the the inferior concha is a inferior concha is a separate boneseparate bone

The cavity below each The cavity below each concha is called a concha is called a meatusmeatus and are named and are named as as superiorsuperior, , middlemiddle & & inferiorinferior corresponding to corresponding to the conchaethe conchae

The small space above The small space above the superior concha is the superior concha is called the called the sphenoethmoidal recesssphenoethmoidal recess

• The middle meatus is The middle meatus is continuous in front with continuous in front with a depression called thea depression called the atriumatrium

• Atrium is limited bove Atrium is limited bove by a ridge calledby a ridge called agar agar nasinasi

• Below and in front of Below and in front of atrium, and just within atrium, and just within the nostril lies thethe nostril lies the vestibulevestibule

The The conchaeconchae increase the surface increase the surface area of the nasal area of the nasal cavitycavity

TheThe recess recess & & meatimeati receive the receive the openings of the:openings of the: Paranasal Paranasal

sinusessinuses Nasolacrimal ductNasolacrimal duct

Sphenoethmoidal Sphenoethmoidal recess:recess: Receives Receives the opening of the the opening of the sphenoidal sinussphenoidal sinus

Superior meatus:Superior meatus: Receives the opening Receives the opening of the of the posterior posterior ethmoidalethmoidal sinussinus

Inferior meatus:Inferior meatus: Receives the opening Receives the opening of theof the nasolacrimal nasolacrimal duct. duct. The opening is The opening is guarded by a guarded by a valvevalve, , a fold of mucous a fold of mucous membranemembrane

Middle meatus:Middle meatus: • Shows a rounded eminence, Shows a rounded eminence,

the the ethmoidal bullaethmoidal bulla, caused , caused by the bulging of the by the bulging of the underlying underlying middle ethmoidal middle ethmoidal sinussinus, which opens on its , which opens on its upper border.upper border.

• A curved groove, A curved groove, hiatus hiatus semilunarissemilunaris, lies below the , lies below the bulla. Hiatus receives the bulla. Hiatus receives the opening of the opening of the maxillary sinusmaxillary sinus

• Anterior end of hiatus leads Anterior end of hiatus leads to funnel-shapedto funnel-shaped infundibuluminfundibulum, which receives , which receives the openings of the the openings of the frontal & frontal & thethe anterior ethmoidal anterior ethmoidal sinusessinuses

Lining of the Nasal CavityLining of the Nasal Cavity VestibuleVestibule is lined by is lined by

modified modified skinskin, and has , and has short, curved hair called short, curved hair called vibrissaevibrissae

The The roofroof, , upper part of the upper part of the septumseptum, , upper surface of upper surface of the superior conchathe superior concha, and , and the the sphenoethmoidal sphenoethmoidal recess recess are lined by the are lined by the olfactory mucosa olfactory mucosa

The The rest of the cavity rest of the cavity is is lined by the lined by the respiratory respiratory mucosamucosa

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Olfactory MucosaOlfactory Mucosa Contains Contains olfactory cells olfactory cells (bipolar sensory (bipolar sensory

ganglion cells), which serve as ganglion cells), which serve as receptors for receptors for olfactory stimuli.olfactory stimuli.

Distinct smells are far more numerous than Distinct smells are far more numerous than tastestastes

The The sense of smell sense of smell plays a major role in the plays a major role in the flavor of foods flavor of foods and it is common for and it is common for individuals who lose their sense of smell to individuals who lose their sense of smell to report that food loses its taste. (food seems report that food loses its taste. (food seems somewhat tasteless when a person has cold)somewhat tasteless when a person has cold)

Most air breathed in normally flows through Most air breathed in normally flows through the nose but only a small part reaches the the nose but only a small part reaches the olfactory mucosa, enough to get a response olfactory mucosa, enough to get a response to an odor. to an odor. SniffingSniffing, however, increases the , however, increases the flow of air over the smell receptor cells, flow of air over the smell receptor cells, greatly increasing their exposure to odors. greatly increasing their exposure to odors.

Respiratory MucosaRespiratory Mucosa Pseudostratified ciliated columnar epithelium Pseudostratified ciliated columnar epithelium

with goblet cellswith goblet cells Rests on Rests on thick network of thin walled veins thick network of thin walled veins that that

warms the air warms the air as it flows through the cavityas it flows through the cavity GlandsGlands produce ‘mucus’, which: produce ‘mucus’, which:

moisten the airmoisten the air cleans the air cleans the air by trapping the incoming by trapping the incoming

bacteria and foreign debrisbacteria and foreign debris Cilia Cilia help in help in moving the contaminated mucus moving the contaminated mucus

posteriorly posteriorly towards the throat, where it is towards the throat, where it is swallowed and digested by the stomach juicesswallowed and digested by the stomach juices

NerveNerve Supply Supply Nasal cavity receives Nasal cavity receives sensorysensory

& & visceralvisceral innervationinnervationSensory innervationSensory innervation Olfactory mucosaOlfactory mucosa supplied by supplied by

olfactory nervesolfactory nerves Nerves of general sensation Nerves of general sensation

are derived from are derived from opthalmicopthalmic & & maxillary nervesmaxillary nerves Anterior part Anterior part supplied by the supplied by the

anterior ethmoidal nerve anterior ethmoidal nerve (branch of opthalmic nerve)(branch of opthalmic nerve)

Posterior part Posterior part supplied by supplied by nasalnasal, , nasopalatinenasopalatine and and palatine branches palatine branches (of (of maxillary nerve)maxillary nerve)

Visceral InnervationVisceral Innervation Sympathetic fibers Sympathetic fibers arise arise

from neurons of from neurons of superior superior cervical ganglioncervical ganglion and are and are distributed through distributed through plexuses around the plexuses around the arteriesarteries, supply mainly , supply mainly vascular smooth musclevascular smooth muscle

Parasympathetic fibers Parasympathetic fibers arise arise from neurons of tfrom neurons of the he pterygopalatine ganglionpterygopalatine ganglion that that course in the course in the nasopalatine nasopalatine nervenerve ( (branch of maxillarybranch of maxillary) ) and its branches, supply the and its branches, supply the mucosal glandsmucosal glands. .

Arterial SupplyArterial Supply Sphenopalatine artery Sphenopalatine artery

(branch of the maxillary (branch of the maxillary artery) artery) is the main supplyis the main supply

Alar and septal branches of Alar and septal branches of superior labial artery superior labial artery (branch (branch of the facial artery)of the facial artery)

Anterior & posterior Anterior & posterior ethmoidal arteries ethmoidal arteries (branches (branches of the ophthalmic artery)of the ophthalmic artery)

The arteries make a rich The arteries make a rich anastomosis in the region of anastomosis in the region of the vestibule, and anterior the vestibule, and anterior portion of the septumportion of the septum

Venous DrainageVenous Drainage:: VeinsVeins begin as a rich plexus in the begin as a rich plexus in the

submucosa, accompany the corresponding submucosa, accompany the corresponding arteries, and drain into the arteries, and drain into the facialfacial, , ophthalmicophthalmic, , and and sphenopalatine veins. sphenopalatine veins.

LymphaticLymphatic DrainageDrainage:: The lymphatics from the:The lymphatics from the:

Vestibule Vestibule drain into the drain into the submandibularsubmandibular lymph nodeslymph nodes

Rest of the cavity Rest of the cavity drains into the drains into the upper upper deep cervicaldeep cervical lymph nodes lymph nodes

Functions of Nose & Nasal CavitiesFunctions of Nose & Nasal Cavities Air conditioningAir conditioning: warming, cleaning and humidifying the : warming, cleaning and humidifying the

inhaled airinhaled air Add resonance to the voiceAdd resonance to the voice Vocal sounds are also produced in the nasal cavity thus Vocal sounds are also produced in the nasal cavity thus

aiding in vocalisationaiding in vocalisation Involved in the Involved in the special sense of smellspecial sense of smell Central role of the nose in Central role of the nose in facial appearancefacial appearance

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Paranasal SinusesParanasal Sinuses Air filled cavities Air filled cavities located in the located in the

bones around the nasal cavity: bones around the nasal cavity: ethmoid, sphenoid, frontal ethmoid, sphenoid, frontal bones & maxillaebones & maxillae

Lined by respiratory mucosa Lined by respiratory mucosa which is continuous with the which is continuous with the mucosa of the nasal cavitymucosa of the nasal cavity

Drain into the nasal cavity Drain into the nasal cavity through relatively small through relatively small aperturesapertures

DrainageDrainage of the sinuses mainly depends on the movement of the ciliamovement of the cilia, which , which propel the mucus toward their openings in the nasal cavity

The development of sinuses The development of sinuses begins in 3-4 month, but begins in 3-4 month, but only only maxillarymaxillary & & ethmoid ethmoid sinuses are present in sinuses are present in rudimentary form at birth. rudimentary form at birth. The The frontalfrontal & & sphenoidalsphenoidal sinuses are not clinically sinuses are not clinically perceptible at birth and can perceptible at birth and can rarely be demonstrated on rarely be demonstrated on plain x-ray before two years plain x-ray before two years of age.of age.

Continue to grow postnatallyContinue to grow postnatally Enlarge appreciably after Enlarge appreciably after 88thth

year year & become fully formed & become fully formed at adolescenceat adolescence

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From a 3 months old fetus, showing ethmoid & maxillary sinuses

FunctionsFunctions

Lighten the skullLighten the skull Act as resonant chambers for speechAct as resonant chambers for speech The respiratory mucosal lining helps in The respiratory mucosal lining helps in

warming, cleaning and moistening the warming, cleaning and moistening the incoming airincoming air

Maxillary SinusesMaxillary Sinuses• Located within the Located within the body of the body of the

maxillamaxilla• PyramidalPyramidal in shape with the in shape with the

base forming the lateral wall of base forming the lateral wall of nose & the apex lies in the nose & the apex lies in the zygomatic process of the zygomatic process of the maxillamaxilla

• RoofRoof: formed by the : formed by the floor of the floor of the orbitorbit

• FloorFloor: formed by the : formed by the alveolar alveolar borderborder. Roots of 1. Roots of 1stst and 2 and 2ndnd premolars and the 3premolars and the 3rdrd molar molar (sometimes canines) project (sometimes canines) project into the sinusinto the sinus

• Opens into the Opens into the middle meatus middle meatus through the hiatus semilunaristhrough the hiatus semilunaris

• Supplied by Supplied by superior alveolar superior alveolar & & infraorbital nervesinfraorbital nerves

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Frontal SinusesFrontal Sinuses TwoTwo in number in number Located within the Located within the

frontal bonefrontal bone, separated , separated from each other by a from each other by a bony septumbony septum

TriangularTriangular in shape, in shape, extending backward extending backward into the into the roof of the orbitroof of the orbit

Opens into the Opens into the middle middle meatusmeatus through the through the infundibuluminfundibulum

Supplied by the Supplied by the supraorbital nervesupraorbital nerve

Ethmoidal SinusesEthmoidal Sinuses LocatedLocated within the within the

ethmoid boneethmoid bone, , between the nose and between the nose and the orbitthe orbit

Divided into Divided into three three groupsgroups: : anterioranterior, , middlemiddle & & posteriorposterior

Anterior group Anterior group opens opens into the into the infundibuluminfundibulum, , middlemiddle opens on the opens on the bullabulla, and , and posteriorposterior into the into the superior superior meatusmeatus

Supplied by the Supplied by the anterioranterior and and posterior posterior ethmoidal nervesethmoidal nerves

Sphenoidal SinusesSphenoidal Sinuses

TwoTwo in number in number Located within the Located within the

body of sphenoidbody of sphenoid Open into the Open into the

sphenoethmoidal sphenoethmoidal recessrecess

Supplied by the Supplied by the posterior ethmoidal posterior ethmoidal nervenerve

Clinical NotesClinical Notes Epistaxis:Epistaxis: Little’s area, Little’s area,

common site of bleeding common site of bleeding from nose from nose

Inflammation of the nasal Inflammation of the nasal mucosamucosa, , RhinitisRhinitis, results in , results in nasal congestion and nasal congestion and excessive production of excessive production of mucus leading to ‘postnasal mucus leading to ‘postnasal drip’drip’

Infections of the nasal Infections of the nasal cavity cavity can extend to the:can extend to the: Paranasal sinusesParanasal sinuses Nasolacrimal duct & Nasolacrimal duct &

lacrimal saclacrimal sac

Inflammation of mucosa of Inflammation of mucosa of the sinusesthe sinuses, , SinusitisSinusitis, , causes excessive production causes excessive production of mucus leading to of mucus leading to obstruction of the drainage obstruction of the drainage of sinuses. This results in of sinuses. This results in headache and change in the headache and change in the voicevoice

Infection of frontal & Infection of frontal & anterior ethmoidal sinusanterior ethmoidal sinus can can easily spread to maxillary easily spread to maxillary sinus because of the sinus because of the location of their openingslocation of their openings

Infection of upper teethInfection of upper teeth can can lead to inflammation of the lead to inflammation of the maxillary sinusmaxillary sinus

Extraction of an infected Extraction of an infected upper tooth upper tooth may result in a may result in a fistulafistula

The The maxillary sinus maxillary sinus is most is most commonly the site of commonly the site of infection infection

The inflamed mucosa results in excessive production of mucus as well as narrowing of its opening in the nasal cavity

The position of the drain causes problems in that mucus can collect in the sinus below the drain. In this situation, the sinus will only drain if the patient lies on their opposite side.

Pressure from the trapped fluid/mucus causes sinus pain

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