1. Anatomy & physiology of Nose
External nose pyramidal in shape, consists of bony &cartilageneous part, Bony part nasal bone&
frontal process of the maxilla.Cartilageous part upper lateral cartilage,lower lateral cartilage. Lower
free border of upper lateral cartilage is seen intanasally limen vestibule orNasal valve. Lateral crus
called alar cartilage& medial crus forming the columella.Skin over lying bone thin &mobile ,over
cartilage thick &adherent contain sebaceous gland> Hypertrophy>Rhinophyoma.
Internal Nose; a)Vestibule of Nose,skin lined portion contain hair follicles (vibrissae)
b)Mucosa lined portion;nasal cavity proper, pseudostriatifed columnar Epithelium +
goblet cells.
c) Olfactory region; above the concha pale in color.
Nasal cavity proper
Lateral wall is convulated by 3turbinates,&corresponding 3 meatus, anterior end of middle meatus
is a ridge /elevation called Agger nasi .
Osteomeatal complex; Agger nasi cells, Uncinate process, Hiatus seminularis,Bulla
ethmoidalis,middle meatus,osteum of maxillary sinus,Infundibulum.
Medial wall : Quadilateral cartilage ,perpendicular plate of ethmoid bone, Vomer. Minor
contribution from Nasal crest of maxilla, nasal crest of palatine bone, Rostrum of the sphenoid
bone.
Roof is formed by Cribriform Plate of ethmoid bone(Mainly),Nasal bone(anterior sloping) Body of
sphniod ( posterior sloping).
Floor is formed by Hard plate( palatine process of maxilla ant 3/4th& horizontal process of palatine
bone post 1/4th.)
Blood supply of nose: ant ethmoidal, post ethmoidal, Sphnopalatine,greater palatine, superior labial
br. Of facial artery
The lamellae; The ethmoid sinus is commonly referred to as the labyrinth due to its complexity.The
complex ethmoidal labyrinth of the adult can be reduced into series of lamellae based on
embryological precursors,they are helfpful in maintaining in ethmoid procedures.
The first lamella is the uncinate process
The 2nd lamella corresponds to the ethmoidal bulla
3rd lamella is the basal or ground lamella of middle turbinate.It divided the anterior & posterior
ethmoid cells.
The fourth is the lamella of the superior turbinate.

2. Agger nasi: prominence on the lateral wall just anterior to the middle turbinate.frequently
pneumatized by an agger nasi cell that arises from superior aspect infundibulum.
The agger cell is bordered anteriorly by the frontal process of the maxilla,superiorly by frontal
sinus ,anteriolaterally by nasal bone, inferolaterally by the uncinate process ,inferolaterally by
lacrimal bone.
Uncinate process; means hook shaped ,approximately 3 to4 mm wide, 1.5 to 2 cm in
length,posterior margin free,form anterior boundary of the hiatus semilunaris.forms medial wall of
infundibuum. Inferiorly it attach with inferior turbinate.
Nasal frontanelles; anterior &posteror frontanelle lie inferior aspect of the uncinate
process,posterior frontanelle much larger,accessory ostia of maxillary sinus may be in the posterior
frontanelle.
Ehtmoid bulla; most constant &largest of the anterior ethmoid cells.located in the middle meatus,
posterior to uncinate process, &anterior to basal lamella.
Superiorly , anterior wall of the ethmoid bulla (or bulla lamella ) can extend to the skull base & form
posterior limit of frontal recess. If the bulla does not reach the skull base ,a suprabulbar recess is
formed between the skull base & superior surface of the bulla.
Posteriorly ,the bulla may blend with the basal lamella or have a space between it & basal lamella
(retrobulbar recess or lateral sinus). The retrobulbar recess may invaginate the basal lamella for a
variable distance . Occasionally extending the anterior air cell system as far posteriorly as the
anterior wall of the sphenoid sinus.
Hiatus semilunaris:is a crescent –shaped gap between posterior free margin of the uncinate process
&anterior wall of the ethmoid bulla.It is a passage that middle meatus communicates with the
infundibulum.
Infundibulum; is the funnel shaped passage through which secretionse are transported into middle
meatus from anterior group of sinuses.Bounded medially by uncinate process , laterally by lamella
papyracea.
Ostiomeatal unit or complex; functional unit of the anterior groups of cells that includes Agger nasi
cells, uncinate process,hiatus semilunaris,Bulla ethmoidalis,ostia of the anterior ethmoid, maxillary
& frontal sinus, Infundibulum and middle meatus.
Frontal recess &sinus;The frontal recess is the most anterior & superior aspect of the anterior
ethmoid sinus that connect with the frontal sinus.The frontal recess tapers as it approaches
superiorly located internal os of the frontal sinus,above the os it again widen as anterior posterior
table diverge to their respective position.(an hour glass like )
The boundaries of the frontal recess are:
The lamella papyracea laterally, the middle turbinate medially, the posterior superior wall of the
aggar nasi cell anteriorly, the anterior wall of ethmoid bulla posteriorly.

3. Ethmoid roof & Cribriform plate;
Typically ,the ethmoid roof slopes inferior medially, & is thinner medially than laterally (by a factor of
10).Medially the roof is formed by the lateral lamella of the cribriform which is variable in its
vertical height. A low lying or asymmetrical skull base is a set up for a CSF leak if not recognized prior
to operation.
Keros describe the three types of formation of the ethmoid roof based upon the vertical height of
the lateral lamella.
Keros type I; short vertical height to the lateral lamella(1-3mm)
Keros typeII ; 4 to 7mm depth to the olfactory fossa.
Keros type III; 8 to 16mm depth to the olfactory fossa.
Keros type III with a long ,thin lateral lamella forming a significant part of the medial part of the
ethmoidal sinus is said to carry the greatest risk of inadvertent intracranial injury.
Sphenoethmoidal (Onodi ) cell
Onodi stress that when the most posterior ethmoid cell was highly pneumotized it could extend
posteriorly along the lamina papyracea into anterior wall of the sphenoid .if this occurred ,the optic
nerve & carotid artery ,both usually considered to border the lateral aspect of the sphenoid sinus,
would usually become intimately related to the posterior ethmoid cell.(onodi cell)
Nerve supply of Nose;
A) Sensory by maxillary div of Trigeminal nerve through pterygopalatine ganglia.
B)Autonomic suppllied by nerve to the pterygoid canal (vidian nerve)
Sympathetic from upper 2 thoracic segments (superior cervical ganglia) Travel in Deep
petrosal nerve to sphenopalatine ganglion>Vasomotor. Parasympathetic from greater superficial
petrosal nerve to nerve to the pterygoid canal then to sphenopalatine ganglion.>Secretomotor.
Infra-orbital nerve supply vestibule of nose.
Sphenopalatine ganglia can be blocked by Loal anaesthetic socked cotton pledget on post end ofthe
middle turbinate
Ant ethmoidal nerve can be blocked by Local anaesthetic soaked cotton pledget on the inside of
nasal bone.

4. Physiology of the Nose
1)Air conditioning function of the Nose
1) Filtration &purification: vibrissae at nasal vestibule adhere to dust particles ,pollen,Bacteria
greater than 3μm while nasal mucosa traps particles as fine as .5-3μm.Particles less than .
5μm pass though nose into lower airways without difficulties.
2) Temperature control:Temperature of inspired air can vary from -50 to50ºC.High vascular
sinusoid direct flow of blood,latent heat of evaporation.
3) Humidification:Inspiration ;saturation follows the temperature rise rapidly.Despite variation
in temperature of inspired air ,air in the post nasal space is approximately 31c & is 95%
saturated.
Expiration;The temperature of the expired air at the back ot the nose is
slightly below body core temperature& is saturated.As the temperature
drops along the nose some water condenses onto the mucosa.The
temperature in the ant nose at the end of the expiration is 32c &
approximately 30c at the of inspiration.Approximately 1/3 rd of the of the
water required to humidify the inspired air is recovered in this way. People
who breathe in through the nose &out though the mouth will dry the nasal
mucosa.
Water also comes from serous glands,expired air, nosolacrimal
duct,Capillary permeability.
Moisture is essential for integrity & function of ciliary epithelium. At least 50% relative humidity is
needed for ciliary function. Dry mucosa stop in 8 -10 minutes.
Moisture is essential for gas exchange.Nasal obstruction >Dry mouth >Gas exchange affected> ↓O2
&↑Co2.
2)Respitory function of Nose
Inspiration: air flow is directed upwards & backwards from nasal valve,mainly over ant part of the
inf. Turbinate.It then spilts into two below &over the middle turbinate.,rejoining into the post
choana.Very little air passes though olfactory region. So weak odorous substances have to be
sniffed .
Expiration; Air current follows the same course as inspiration.Friction offered at limen nasi converts
into eddies under inf. Turbinate.&middle turbinates.This ventilates the sinuses.
Anterior nasal valve;
Is formed by the lower edge of the upper lateral cartilage, the ant .end of the inf turbinate&
adjacent nasal septum.

5. Nasal cycle
Nasal cycle produce by vascular activity.Cyclical change s occur between 4 to 12 hrs. Can be
demonstrated 80% of adult . physiological significance is uncertain. Various factors modify the nasal
cycle, infection,allergy, exercise,hormone,pregnancy, fear ,emotion sexual activity.
3)Protection of the lower air way
Mucocilliary mechanism: nasal mucosa rich in goblet cells secrets mucus (Glycoprotein).Mucus
blanket consists of superficial mucus layer& deep serous layer. (conveyer belt)
Composition of mucus;
1)water &ions from transduction,
2) Glycoprotein
3)Enzymes lysozymes, lactoferrin.
4) Circulatory proteins; Compliments ,macroglobulin, c reactive protein.
5)Ig – A ,E G M,D
6)Cells Surface epithelium, basophils, eosinophil leuocytes.
Cillia beats 10 -20 times /sec, Effective stroke & Recovery stroke.
Protein in nasal secretion
a) Lactoferrin > serous cells >prevent growth of staphylococci &pseudomonas.
b) Lysozymes >serous cells>Act on Bacteria
c) Antiproteases ,α-antitrypsin α1-antichymotrypsin,α2-macroglobulin.
d) Complements
e) Immunoglobulin>All Immunoglobulin are present, IgA are 50%.
Nasal vasculature
Nasal vasculature devoid of constricting smooth muscle.Anastomoting arteries spiral upward
through cavernous plexus of veins.It bypasses the surface vessels.Capillaries drain into venous
sinusoid.Cavernous plexus of veins without valve,Blood flow regulated by cushion or throttle vein
which have a longitudinal muscle coat (pseudoerectile).

6. Sneezing reflex,
It is a protective reflex. Chemical irritation, Temperature change, Physical stimuli causes facial
movement, Lacrimation, nasal secretion, vascular engorgement.
Endotracheal intubation through nose cause unexplained Bradycardia.
Drugs acting on Nose
Sex hormone> oestrogen concentrate on nose> nasal obstruction& Rhinorrhea,
Thyroxine> Hyperthyroidism give rise Rhinitis.
Hypothyroidism cause deposition of mucopolysaccharide.
Glucocorticoid> Fluticasone may contract smooth muscle of arterioles directly.
4)Vocal Resonance
5) Olfaction.

10. is form nasal septum. ed by the lower edge of the upper lateral cartilage. Ant. End of the inf.
Turbinate & adjacent