ANATOMY, PHISIOLOGY and ILLNESSES of the NOSE and PARANASAL SINUSES
Anatomy and physiology of nose and paranasal sinuses
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Transcript of Anatomy and physiology of nose and paranasal sinuses
ANATOMY & PHYSIOLOGY
OF NOSE ANDPARANASAL
SINUSESBRIG ANWAR UL HAQ00923018513303
PAKISTAN
ANATOMY OF NOSEEXTERNAL NOSE
• Osteocartilagenous framework: Upper 1/3rd - BonyLower 2/3rd – Cartilagenous
• Bony frameworka) Nasal bonesb) Nasal processes of frontal bonec) Frontal processes of maxilla
APPLIED ANATOMY• Dangerous area of face- The lower part of
external nose and the upper lip. Infection may spread to cavernous sinus through inferior ophthalmic vein via anterior facial vein which have no valves
• Dangerous area of nose- olfactory area Infection may spread into meninges along the pia and arachnoid sheath of olfactory nerves. This area is also connected to superior sagittal sinus and cavernous sinus by venous channels
ANATOMY OF NOSEEXTERNAL NOSE• Cartilagenous frameworka) Upper lateral cartilagesb) Lower lateral cartilages (alar cartilages)c) Lesser cartilages (sesamoid cartilages)d) Septal cartilage
Clinical significance: limen nasi (nasal valve) is the narrowest area in the upper airway
ANATOMY OF NOSEEXTERNAL NOSE
• Nasal valve: Formed by lower edge of upper lateral cartilages, the anterior end of inferior turbinate and adjacent nasal septum.
• Cottle’s test: used in nasal obstruction due to abnormality of nasal valve.
ANATOMY OF NOSEEXTERNAL NOSE
• Nasal musculature:a) Procerusb) Nasalis (transverse and alar part)c) Levator labi superioris alaque nasid) Anterior and posterior dialator narise) Depressor septiNasal skin: skin over nasal bone and upper
lateral cartilage is thin and freely mobile while that on alar cartilages is thick and adherent and contains sebaceous glands
ANATOMY OF NOSEEXTERNAL NOSE
• Blood supply: – facial and ophthalmic arteries and
veins• Lymphatic drainage:
– preauricular– submandibular lymph nodes
ANATOMY OF NOSEINTERNAL NOSE
• It is divided into right and left nasal cavities by nasal septum.
Each nasal cavity consists of a) Skin lined portion-vestibule (contains
sebaceous glands, hair follicles, vibrissae)b) Mucosa lined portion-nasal cavity proper
ANATOMY OF NOSEINTERNAL NOSE
• Nasal cavity proper: bounded by lateral wall, medial wall, roof and a floor.
• Floor: Formed by– Palatine process of maxilla (anterior 3/4th )– Horizontal process of palatine bone (posterior
1/4th )
ANATOMY OF NOSEINTERNAL NOSE
• Roof: formed by– Anterior sloping part by nasal bones– Posterior sloping part by body of sphenoid– Middle horizontal part by cribriform plate of
ethmoid through which olfactory nerves enter the nasal cavity
ANATOMY OF NOSEINTERNAL NOSE
• Medial wall of nasal cavity (nasal septum)
ANATOMY OF NOSEINTERNAL NOSE (Septum)
• Nasal septum consists of three parts a) Columellar septumb) Membranous septum (lies between columella and
caudal border of septal cartilage)c) Septum proper: consists of osteocartilagenous
framework covered with nasal mucous membrane
ANATOMY OF NOSEINTERNAL NOSE(Septum)• Septum proper: principal constituentsa) Perpendicular plate of ethmoid postero-
superiorlyb) Vomer infero-posteriorlyc) Septal cartilage (quadrilateral cartilage)• These articulate with following bones to
complete the septum a) Superiorly-frontal bone, nasal bone,
rostrum of sphenoid.b) Inferiorly anterior nasal spine of maxilla,
nasal crest of maxilla and palatine bones
BLOOD SUPPLY-NASAL SEPTUM
• Little’s area: Situated in the antero-inferior part of nasal septum just above the vestibule. Four arteries-– anterior ethmoidal– septal branch of superior labial– septal branch of sphenopalatine– greater palatine
• anastamose here to form kiesselbach’s plexus.
BLOOD SUPPLY-NASAL SEPTUM
NERVE SUPPLY-NASAL SEPTUM
ANATOMY-LATERAL WALL OF NASAL CAVITY
ANATOMY-LATERAL WALL OF NASAL CAVITYa) Ascending process of maxillab) Nasal bonec) Ethmoidd) Medial part of maxillae) Inferior turbinatef) Perpendicular plate of palatine boneg) Medial pterygoid plate
ANATOMY-LATERAL WALL OF NASAL CAVITY• Three bony projections
– turbinates or conchae-• Superior (part of ethmoid) • Middle (part of ethmoid)• Inferior (separate bone)
• Sometimes 4th turbinate concha suprema
• Bellow and lateral to each turbinate – corresponding meatus
ANATOMY-LATERAL WALL OF NASAL CAVITY• Inferior meatus-
– nasolacrimal duct opens in its anterior part.• Middle meatus-
– consists of bulla ethmoidalis, hiatus semilunaris, infundibulum. Frontal, maxillary and anterior ethmoidal sinuses open into middle meatus.
ANATOMY-LATERAL WALL OF NASAL CAVITY• Superior meatus-
– Posterior ethmoidal sinuses• Sphenoethmoidal recess-
– Sriangular fossa above the superior meatus.– Sphenoidal sinus
ANATOMY-LATERAL WALL OF NASAL CAVITY
BLOOD SUPPLY-LATERAL WALL OF NASAL CAVITY
NERVE SUPPLY-LATERAL WALL OF NASAL CAVITY
AUTONOMIC NERVE SUPPLY- NASAL CAVITY
• Sympathetic supply- – Superior cervical sympathetic ganglion – Internal carotid plexus – vidian nerve – sphenopalatine ganglion.
AUTONOMIC NERVE SUPPLY- NASAL CAVITY
• Parasympathetic supply- – facial nerve – greater superficial petrosal nerve – vidian nerve – sphenopalatine ganglion.– Nasal branches from sphenopalatine ganglion
SENSORY NERVE SUPPLY-NASAL CAVITY• Common sensation
– Trigeminal nerve • ophthalmic • maxillary divisions.
• Special sensory (smell) – Olfactory nerves.
LYMPHATIC DRIANAGE-NASAL CAVITY
• Upper deep cervical nodes drain the nasal cavity directly or via the retropharyngeal nodes.
PARANASAL SINUSES-ANATOMY
• These are air filled spaces• Certain bones of skull• Direct communication with nasal cavity
through their ostia• Four on each side divided as
PARANASAL SINUSES-ANATOMY
a) Anterior group- a) Maxillaryb) Frontalc) Anterior ethmoidal
b) Posterior group- a) Posterior ethmoidb) Sphenoid
Development of Sinuses• Outpouching from mucus membrane of
nose• at birth:-Maxillary and ethmoidal present• At 6-7 yrs:- frontals and sphenoids• At 17-18 :- all full developed
Drainage
Objectives• To know anatomical location• Their connections & significance• Development• Neurovascular supply• Applied anatomy
Introduction
• Air containing cavities.
• Each sinus are named after the bone it resides in.
• 4 pairs :-• frontal • maxillary, ethmoidal,
sphenoidal
Lateral view
Anterior view
Maxillary sinuses
• Largest PNS• Pyramidal shape • Base pointing to
lateral wall of nose• Apex laterally in
the zygomatic process
• Capacity 15 ml
Relations • Anterior:-– Facial surface of
maxilla• Posterior:
– Infratemporal and pterygopalatine fossa
• Medial:- – Middle and inferor
meatus• Floor:-
– Alveolar and palatine processes of maxilla
• Roof:-– Floor of orbit
BLOOD SUPPLY MAX SINUS• Blood supply :
– Facial– infra orbital– greater palatine arteries.
• Lymphatic drainage : – Submandibular nodes.
• Nerve supply : – Infra orbital, anterior– middle and post superior alveolar nerves
Frontal sinus • Resides in frontal bone
• 2nd largest• Asymmetrical• Usually paired-
sometimes one, three or none!
Relations -Frontal Sinus• Anterior:-
– Skin over the forehead
• Inferior:-– Orbit & its contents
• Posterior:- – Meningeal and frontal lobe
of brain
Neurovascular supply• Blood supply –
– Supra orbital arteryAnterior ethmoidal arteries.
• Venous return –– Anastomotic veins in supra orbital notch, connecting
supra orbital and supra ophthalmic veins.
• Lymphatic drainage – – Submandibular nodes.
• Nerve supply – – Supra orbital nerve traversing the floor of the sinus.
Ethmoidal sinuses• Resides in ethmoid
bone• 3 groups:-
– anterior – Posterior– sphenoethmoidal
recess• Number varies from
3-18• Present from birth
Relation(Ethmoids)
• Roof:- – anterior cranial fossa
• Lateral:- – orbit (separated by
lamina papyracea)• Optic nerve lies close
to posterior ethmoidal cells
Neurovascular supply(Ethmoids)• Blood supply :
– Sphenopalatine artery Anterior and posterior ethmoidal artery.
• Lymphatic drainage :– Submandibular nodes
Retropharyngeal nodes.
• Nerves : – Anterior and posterior ethmoidal
nerves.Orbital branches of pterygopalatine ganglion..
OSTEOMEATAL COMPLEX• The middle meatus
– Space below and lateral to the middle turbinate,– Functionally referred as osteomeatal complex– Drainage pathways
• Anterior ethmoids• Maxillary • Frontal sinuses.
• The middle meatus – Pathophysiology of chronic rhinosinusitis.
OSTEOMEATAL COMPLEX-RELATED STRUCTURES
• Bulla ethmoidalis- The ethmoid bulla is one of the most constant and largest of the anterior ethmoid air cells. It is located within the middle meatus directly posterior to the uncinate process and anterior to the basal lamella of the middle turbinate.
OSTEOMEATAL COMPLEX-RELATED STRUCTURES
• Hiatus semilunaris- Hiatus semilunaris is a crescent shaped gap between the posterior free margin of the uncinate process and the anterior wall of the ethmoid bulla, through this passage the middle meatus communicates with the ethmoid infundibulum .
OSTEOMEATAL COMPLEX-RELATED STRUCTURES• Ethmoidal infundibulum - Ethmoidal
infundibulum is the funnel-shaped passage through which the secretions from various anterior ethmoid cells, the maxillary sinus, and, in some cases, the frontal sinus are transported or channeled into the middle meatus.
OSTEOMEATAL COMPLEX-RELATED STRUCTURES• Uncinate process- floor and medial wall of
infundibulum is formed by the uncinate process of the ethmoid. This structure is nearly sagittally oriented, nearly paralleling the ethmoidal bulla. It is approximately 3 to 4 mm wide and 1.5 to 2 cm in length.
Sphenoid sinus
• Resides in body of sphenoid
• Paired• Asymmetrical• Not present at birth
Relation(Sphenoid)• Lies below to sella turcica• Sphenoid effusion shows skull base fracture• Related to
– optic tractchiasma– internal carotid artery
Sphenoid Sinus• Blood supply :
– Posterior ethmoidal artery.• Lymphatic drainage
– Retropharyngeal nodes.• Nerve supply :
– Posterior ethmoidal nerve.
Microscopic Anatomy
• Lined by mucus membrane
• Ciliated columnar epithelium
• Goblet cells secretes mucus
• Cilia are more marked near ostia.
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Introduction• organ of smell• Organ of respiration• It warms, cleans and humidifies the
inspired air, cools and remove the water from the expired air
• It also adds quality to speech production
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Introduction• The ENT surgeon should distinguish
normal nasal function from pathological symptoms to prevent unnecessary surgery
• Although the nose is a paired structure divided coronally into two chambers, it act as a functional unit
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Function Mechanism
Respiration
Heat exchangeDirection of blood flowLatent heat of evaporationThermoregulation
HumidificationAnterior serous glandsMixed serous and mucus glandsCapillary permaebilityOther body fluids; e.g. tears
Filtration Airflow pattern: laminar/turbulent
Nasal resistance Anatomical, fixedNeurovascular, variable
Nasal fluids and ciliary fuction
Mucus, mucinsProtein including immunoglobulinsCiliary structure and function
Nasal neurovascular reflexes
ParasympatheticSympatheticSensory: axon reflexesSneezingCentral: pulmonary reflexesNasal cycle
Voice modification Nasal escape63
Olfaction
Stimulus Threshold and suprathresholdAdaptation, discrimination and classification
Pathways Neurones in contact with the external environmentTwo neurone peripheral pathway
Higher centresPerceived smell
Trigeminal input PainOlfaction and behaviour Pheromones
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Respiration• Air conditioning unit • Humidification• Heat transfer
– Temperature regulation• Filtration
– Inspired gases contain pollutants, domestic dust particles and pollen, industrial products, bacteria, viruses and tobacco smoke
• Bypasses during exercise• Temperature regulation
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I. Heat Exchange• Inspired air
– Vary from -50 to 50oc
Conduction, convection and radiation• Conduction occurs without flow when heat
is transferred by increased molecular movement
• A temperature gradient leads to convection of currents affect airflow in the nose turbulence
• Flow results in forced convection66
II. Humidification• Vaporization cools the surface • 10 percent of the body heat is lostInspiration• Saturation follows the temperature rise
rapidly
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II. Humidification• Energy required for:
– raising the temperature of inspired air (1/5)– The amount of energy is dependent on ambient
temperature and relative humidity of an inspired air
– Heat of evaporation (4/5)• 10% of body heat loss occurs through the
nose in humans• Air in post nasal space is approximately 31oC
and is 95% saturated2
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Expiration • expired air at the back of the nose
– slightly below body core temperature– saturated
• Some water condenses into the mucosa as the temperature drops along the nose
• The temperature in the anterior nose at the end of the expiration is 32oC and approximately 30oC at the end of inspiration
• Approximately 1/3rd of the water required to humidify the inspired air is recovered in this way
• People who breathe in through the nose and out through the mouth will dry the mucosa
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Water production• Water comes from the serous gland, which are extensive
throughout the nose• During nasal cycle, secretions are lower on the more
obstructed side• Additional water comes from the expired air, the
nasolacrimal duct and the oral cavity• Humidification is reduced by atropine probably acting on
the gland rather than the vasculature3
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III. Airflow• The airflow and the sensation of it are very different• Cold receptors sense airflow• Most of the work of heat and mass transport has
been performed on simple structures with constant cross sections.2
• The flow is turbulent, but is considered laminar at rest• The equations below describe flow, two for laminar
and one for the transition to turbulent flowAirflow : VA = constant
Bernoulli’s equation : P + ½ ρV2 = constant
Reynolds number : Re =
ρ = density (g m-1); V = velocity (m sec-1); A = cross-sectional area (m2); P = pressure (N m-2); d = diameter (m); ƞ = viscosity (g sec-1 m-1) 71
dVρƞ
• Gases flow faster through the choana4
• The characteristic of air flow were similar in different noses regardless of variety of nasal shape
• The cross-sectional flow is maximal at the centre and is zero at the edge
• Bernoulli equation is not strictly applicable since the energy overcoming the viscosity results in an irreversible drop in pressure
• The nose has variable cross section – the pressure and velocity will alter continuously within the system
• Because of the flow is turbulent in an irregular tube, the resistance is inversely proportional to the square of the flow rate5
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Inspiration• Airflow is directed upwards and backwards from the
nasal valve initially, mainly over the anterior part of the inferior turbinate
• It then splits into two, below and over the middle turbinate, rejoining into posterior choana
• Air reaches the other parts of the nose to a lesser degree• The velocity at the anterior valve is 12 - 18 m per sec
during quiet respiration
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Expiration• Expiration lasts longer than inspiration
and is more turbulent• Extrapulmonary airflow is turbulent
because of the direction changes, the calibre varies markedly and walls are not smooth. The surface area is enlarged by the turbinates and the microanatomy of the epithelium
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Nasal resistance• Differs between races• The nose accounts for up to half of the total
airway resistance• Produced by two resistors
– fixed: bone, cartilage and muscle– variable: mucosa
• High in infants (obligatory nose breathers)• Adult breath preferentially through the nose at
rest even though there is a significant resistance
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The anterior nasal valve• Narrowest part of the nose and less well defined
physilogically then anatomically• Greatest resistor – produces the most turbulent
airflow• Formed by the
– lower edge of the upper lateral cartilages– anterior end of inferior turbinate– adjacent nasal septum– surrounding soft tissues
• EMG – – contraction of the dilator naris – increases during exercise
• Alar collapse occurs after denervation77
Nasal cycle• alternate nasal blockage between passages• The changes are produced by vascular activity
particularly the volume of blood on the venous sinusoids (capasitance vessels)
• Cyclical changes - 4 to 12 hours• Can be demonstrated in over 80% of adults• Difficult to demonstrate in children• Nasal secretions are also cyclical with an
increase in secretions in the side with the greatest airflow3 78
Factors modify the nasal cycle• allergy• Infection• Exercise• Hormones• Pregnancy• Fear• Emotions• sexual activity• Vagal overactivity• Puberty
79
•Sympathomymetic•Parasympathetic
IV. Protection of Lower Airway: Mechanical and Chemical
• Removing particles - 30 μm, – pollens from the inspired air
• Dust deposited in the nose• Inspired air travels through 180o and velocity drops
markedly just after the nasal valve• Turbulence increases deposition of particles• Particles in motion - carry on in the same direction• Resistance to change in velocity is greater in irregular
particles because of larger surface area and the number of facets
• Vibrissae will only stop the largest particles80
Nasal secretions• Composed of :–
– Mucus – Water– Glycoprotein – goblet cells– Water and ions –– Submucosal glands– Serous glands
• The anterior part of the nose
• Sinuses has fewer goblet cells and mixed glands
81
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Proteins in nasal secretion1. Lactoferrin
– Serous gland– Bind divalent metal ions – like transferrin in
the circulation– Lactoferrin and transferrin
• Prevent growth of certain bacteria,• Staphylococcus and pseudomonas
2. Lysozymes– Serous glands and tears– Act only on non capsulated bacteria
83
3. Antiproteases– Produced by leukocytes– Increase with infection
4. Complement– C3 – produced by liver and locally by macrophages– Functions: lysis of microorganism, enhancing neutrophil function
(leukotaxis)
5. Lipids6. Ions and Water
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CiliaUltrastructure• Found on the surface of cells in the respiratory
tract• Function: to propel mucus backwards• All cilia have the same ultrastructure • Nasal cilia - relatively short at 5 μm, • Nasal cilia - with up to 200 per cell• 9 paired outer microtubules surround a single
inner pair of microtubules85
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FACTORS AFFECTING CILIARY ACTION
• Drying stops the cilia• Temperature below 10oC and above 45oC• Solutions above 5 % and below 0.2%• pH below 6.4 and above 8.5• Upper respiratory tract infection – damage the epithelium• Ageing
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FACTORS AFFECTING CILIARY ACTION
DRUGS• Acetylcholine - increases the rate• Adrenaline - reduces the rate• Propanolol – reduces the rate• Cocaine hydrochloride (>10%) – causes
immediate paralysis• Corticosteroids – reduces the rate
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V. Protection of Lower Airway: Immunological• IgA • IgE• IgM • IgG• Certain bacterial allergens are neutralized• The T and some B cells interact with microphages, • Dendritic cells are important in the allergic response• cytokines • Leukotrines
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VI. Vocal Resonance• Nose form resonating chamber for certain
consonants in speech• Phonating nasal consonants (M/N/NG) – • Many nasal condition affect the quality of
voice by blocking the passage of air• Rhinolalia clausa – too little air escapes
from the nose• Rhinolalia aperta – too much air escapes
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VII. Olfaction• Olfactory compound need high water and lipid
solubility• The solute in the mucus is presented to the
sensory mucosa
Olfactory area • Area: 200-400mm2
• Receptor cells
StimulusReact with lipid bilayer of the receptor cells at specific sites cells depolarization 91
Adaptation• Olfactoy responses show marked adaptation
and thresholds increase with exposure• Adaptation
– peripheral – central phenomenon
• Cross adaptations
92
factors affecting threshold:• Changes in nasal mucus and its ph• Age – decreases the threshold • Hormones (sex hormones) – increases the
threshold
Olfactory pathways• Olfactory region (high up in nasal cavity)• Olfactory cells and cillia• Central process - olfactory nerves • Pass through the cribriform plate • Olfactory bulb• Olfactory tract • Prepyriform cortex • Amygdaloid nucleus where it reaches consciousness
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Disorders of smell• Anosmia: total loss of smell• Hyposmia: partial loss• Parosmia: perversion of smell –
– Interprets the odour incorrectly– Seen in
• Recovery phase of post influenzal anosmia,• Intracranial tumour
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Conclusion• An understanding of the physiology of the nose
is required to:– Evaluate nasal symptoms– Know its protective role in
• Health • Disease
– Determine the role of investigations in the assessment of airway function and mucociliary clearence
– Understand the action of drugs - nasal mucosa– Assess the smell and taste
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