Anatomy of airway

ANATOMY OF AIRWAY &
ITS ANAESTHETIC
IMPORTANCE
MODERATOR- DR SHIVSHANKAR M
PRESENTED BY – DR SHABBIR

FUNCTION OF NOSE
• The only externally visible part of the
respiratory system that functions by:
– Providing an airway for respiration
– Moistening (humidifying) and warming the
entering air
– Filtering inspired air and cleaning it of foreign
matter
– Serving as a resonating chamber for speech
– Housing the olfactory receptors

NOSE
• The nose is divided into two regions
– The external nose, including the root, bridge,
dorsum nasi, and apex
– The internal nasal cavity
• Philtrum – a shallow vertical groove inferior
to the apex
• The external nares (nostrils) are bounded
laterally by the alae

NASAL CAVITY
• Lies in and posterior to the external nose
• Is divided by a midline nasal septum
• Opens posteriorly into the nasal pharynx via
internal nares
• The ethmoid and sphenoid bones form the
roof
• The floor is formed by the hard and soft
palates

• Inspired air is:
– Humidified by the high water content in the nasal
cavity
– Warmed by rich plexuses of capillaries
• Ciliated mucosal cells remove contaminated
mucus
• Superior, medial, and inferior conchae:
– Protrude medially from the lateral walls ,
Increase mucosal area and Enhance air
turbulence and help filter air
• Sensitive mucosa triggers sneezing when
stimulated by irritating particles

• During inhalation the conchae and nasal
mucosa:
– Filter, heat, and moisten air
• During exhalation these structures:
– Reclaim heat and moisture
– Minimize heat and moisture loss
Sinuses in bones that surround the nasal
cavity
Sinuses lighten the skull and help to warm and
moisten the air

NOSE
 Rigid structure composed of cartilage
and bone
 Septal cartilage divides nasal cavity
into two nasal fossae
 Palate divides nasal cavity and oral
cavity
 Nose divided into 3 regions

 Vestibular area contains sebaceous
glands; secrete sebum
 Keeps vibrissae soft and filter gases
 Olfactory region: pseudostratified
columnar epithelium and olfactory
cells

 Respiratory—highly vascular; ciliated,
pseudostratified columnar epithelium
◦ Contains turbinates or conchae; increase
surface area (166 cm2) for humidification,
heating/cooling and filtering of air
◦ Mucous membranes provide up to 650-
1000 ml of water/day to humidify air

 Goblet cells in mucus membrane
secrete 100 ml/day of mucous; aids in
trapping inspired particles and
prevents them from entering lower
respiratory trace
 Each columnar cell contains 200-250
cilia; beat in waves toward oropharynx
(mouth), 2cm/min

NOSE
 Deflection of nasal septum – diminish
lumen of respiratory airway-prevent
passage of smallest ET Tube-test
Patency of each nostril-side were
obstruction is greatest anteriorly –
easiest to intubate
 Warming and humidifying inspired air
 Intubation is followed by mild tracheitis
–humidification of fresh gas flow can
prevent it

NOSE
 Resistance to airflow through nasal
passages is twice the resistance through
mouth
 Respiration , olfaction , phonation ,
humidification and filtration
 Two nasal fossae extend 10-14 cm from
nostrils to nasopharynx
 Nasal seputm is composed mainly by
perpendicular plate of ethmoid
descending from cribriform plate , septal
cartilage and vomer

NOSE
 Disruption of cribriform plate
secondary to facial trauma or head
injury may allow direct communication
with anterior cranial fossa , thus use of
positive pressure mask ventillation can
led to spread of infection causing
meningitis or sepsis . nasal airways ,
nasotracheal tubes and nasogastric
tubes may inadvertently be
introduced into subarachnoid space

NOSE
 Each nasal fossa provides approx 60
cm2 surface area per side for warming
and humidifying inspired air
 Inferior turbinate limits the size of
nasotracheal tube that can be passed
through nose
 Prolonged nasal intubation can cause
maxillary sinus infection as its drainage
is hindered
 Olfactory area is liminted in upper third of
nasal fossa and respiratory area in lower
third of nasal fossa

NOSE
 10,OOO L of ambient air passes through
nasal airway per day and 1 L of moisture is
added to this air
 Moisture is partly from transudation of fluid
through mucosal epithelium and from
secretions produced by glands and goblet
cells
 These secretions have bactericidal activity ,
foreign body invasion is further reduced by
stiff hairs ( vibrissae ) , ciliated epithelium and
extensive lymphatic drainage
 Kratschmer reflex - bronchiolar constriction
upon stimulation of anterior nasal septum

ANAESTHESIA & HUMIDITY
 PRINCIPAL-Quantity of water vapour
needed to saturate air with water vapour
increases with temprature
 At room temprature of 17 c air contains 2
volumes per cent of water when fully
saturated
 At body temprature of 37 c air in trachea
contains 6 volumes percent of water
vapour , thus nose and respiratory tract
not only have the task of warming
inspired air but also adding large
quantities of water vapour

 In most anaesthetic systems –temperature
of gases reaching patients is
approximately same as room temprature
 TO AND FRO SYSTEM –temperature of
cansiter( near patient mouth ) may rise to
as high as 45 *c , no time is available for
cooling , provides very efficient
humidification
 CIRCLE ABSORPTION SYSTEM –
inspired mixture consists not only fresh dry
gases but some expired gases containing
water vapours at room temprature
 NON –REBREATHING VALVE SYSTEM

METHODS OF
HUMIDIFICATION
 DIRECT INSTALLATION
 WATER-BATH
 MOISTURE EXCHANGER
 MECHANICAL NEBULISER
 ULTRASONIC NEBULISER

PHARYNX
• Funnel-shaped tube of skeletal muscle that
connects to the:
– Nasal cavity and mouth superiorly
– Larynx and esophagus inferiorly
• Extends from the base of the skull to the
level of the sixth cervical vertebra

PHARYNX
• It is divided into three regions
– Nasopharynx
– Oropharynx
– Laryngopharynx

 NOSE
 PHARYNX
 LARYNX

PHARYNX
 12-15 cm long , extends from base of
skull to cricoid cartilage anteriorly and
to inferior border of sixth cervical
border posteriorly
 Widest at level of hyoid bone ( 5 cm )
and narrowest at level of esophagus (
1.5 cm ) which is the most common
site of obstruction after foreign body
aspiration

 Eustachian tube opens into lateral wall of
nasopharynx
 Tonsillar pillars of fauces are present in
lateral wall of oropharynx
 Wall of pharynx contains two layers of
muscle , external circular and internal
longitudnal , each layer is composed of
three paired muscles
 Stylo , salpingo and palatopharyngeous
form the internal layer , they elevate the
pharynx and shorten larynx during
deglutition

 Superior , middle and inferior
constrictors form external layer ,
advance food in coordinated fashion
from oropharynx to esophagus
 Constrictors are innervated by
pharyngeal plexus , inferior constrictor
has additional innervation by recurrent
and external laryngeal nerve
 Internal layer is innervated by
glossopharyngeal nerve

Superior constrictor
Mucous membrane of
oral pharynx
Mucous membrane of
laryngeal pharynx
Middle constrictor
Inferior constrictor
Esophagus
Mucous membrane of nasopharynx

DEFENCE AGAINST
PATHOGENS
 Inhaled particles greater than 10 um
are removed by inertial impaction
upon posterior nasopharynx
 Inhaled airstream changes direction
sharply at 90 degree hence cause
some loss of momentum
 Impacted particles are trapped by
waldeyers ring

 Adenoid hypertrophy may restrict size
of nasotracheal tube
 Lingual tonsil hypertrophy which is
usually asymptomatic has been
reported to be cause of unanticipated
difficult intubation and fatal airway
obstruction
 Retropharngeal and peritonsillar
abscess poses anaesthetic challenges

 Patency of pharynx is vital to patency of
airway and proper gas exchange
 Traditionally its has been taught that in
sedated or anesthetized patient , tongue
fall ( reduction in genioglossus muscle
activity leds to posterior displacment of
tongue ) is cause of upper airway
obstruction , however lately it has been
proved that obstruction occurs as result
of anterio-posterior dimensional changes
at level of soft palate and epiglottis and
not at level of tongue

OBSTRUCTIVE SLEEP APNEA
 Narrowest portion of pharynx – posterior
to soft palate
 Subatmospheric subairway pressure
created by contraction of diaphragm
against resistance of nose can led to
reduction in size of pharyngeal airway
 Longer axis of pharyngeal airway is
transverse however in OSA patients
anterior-posterior axis is predominant
 Application of CPAP appears to increase
the volume and cross-sectional area of
oropharynx

 Collapsible segments of pharynx are
divided into three areas – retropalatal ,
retroglossal and retroepiglottic
 Patency is dependent on contractile
function of pharyngeal dilator muscles
 Tensor palatani retracting soft palate
away from posterior pharyngeal wall
 Genioglossus moving tongue anteriorly
 Muscles moving the hyoid bone
anteriorly including geniohyoid ,
sternohyoid and thyrohyoid

GLOTTIC CLOSURE &
LARYNGEAL SPASM
 Stimulation of superior laryngeal nerve
mainly and to lesser extent trigeminal
and glossopharyngeal nerve endings in
supraglottic region can induce protective
closure of glottis , this short lived
phenomenon is polysynaptic involuntary
reflex
 Nerve endings are highly sensitive to
touch , heat and chemical stimuli ,
sensitive is especially intense in
posterior commissure of larynx

 Tongue fall can be prevented by
extending head at atlanto-occipital region
( chin lift ) and lifting jaw up and forwards
( jaw thrust ) or by placing patient in
lateral position
 Spasm may result from intense surgical
stimulation such as dilation of cervix ,
anus under insufficient anaesthesia , this
is powerful reason why suxamethonium
should be readily available

Oral procedures that promote an increase in
secretions with blood in the airways, such as
adenoidectomy tonsillectomy and laryngeal surgery,
are associated with a higher risk.
Bronchoscopy and upper gastrointestinal
endoscopy can trigger the reflex by direct
stimulation
Certain dye stuff instilled on the eyes to evaluate
the results of nasolacrimal catheterization can
trigger laryngospasm, thus intubation of those
patients or expelling the dye through the
contralateral nostril is recommended .
Anal dilation and correction of hypospadia can
trigger reflex laryngospasm. anesthesia with
neuroaxis block, such as sacral epidural anesthesia,
and maintenance of adequate general anesthesia

 Among inhalational anesthetic agents,
desflurane and isoflurane when used for
induction have an unacceptable rate of
laryngospasm, which is one of the
motives that sevoflurane and halothane
are used for inhalational anesthetic
induction.
 Laryngospasm represents focal seizure
of adductors , this state is initiated by
repeated superior laryngeal nerve
stimulation

NASOPHARYNX
• Lies posterior to the nasal cavity, inferior to
the sphenoid, and superior to the level of the
soft palate , Strictly an air passageway
• Lined with pseudostratified columnar
epithelium , Closes during swallowing to
prevent food from entering the nasal cavity
• pharyngeal tonsil lies high on the posterior
wall
• Eustachian tube and auditory tube open into
lateral surfaces, connect nasopharynx to
middle ear, equalizes pressure of middle ear

OROPHARYNX
• Extends inferiorly from the level of the soft
palate to the epiglottis
• Opens to the oral cavity via an archway
called the fauces
• Serves as a common passageway for food
and air
• The epithelial lining is protective stratified
squamous epithelium
• Palatine tonsils lie in the lateral walls of the
fauces

 Roof of the mouth is formed by the
hard and soft palate
◦ Hard – Bony portion
◦ Soft – Fleshy portion
 Uvula is the soft fleshy structure
 Epithelium is stratified squamous
epithelium which is non-ciliated.
 Palatine (faucial) tonsils are located
on each side of the oral cavity

TONSILS
 Waldeyer's ring is a continuous band of lymphoid
tissue that surrounds the upper pharynx.
 The superior portion of the ring is located in the
nasopharynx and is composed of the adenoids.
Laterally the palatine tonsils and anteriorly the
lingual tonsils complete the ring.
 Tonsillar crypts extend deeply into the body of the
tonsil and are surrounded by lymphoid nodules.
Debris and foreign particles collect within the crypts.
 The epithelium of the tonsils also varies by location.
While the pharyngeal tonsil is covered mainly by
multiple rows of ciliated epithelium, the palatine and
lingual tonsils are covered by stratified, non-
keratinized squamous epithelium.

 primary follicles are formed during embryonic
development and differentiate into secondary
follicles after birth.
 secondary follicles mainly contain B
lymphocytes at various stages of
differentiation, along with scattered T
lymphocytes.
 Tonsillar tumors or infections may result in
ear pain due to referred pain conducted by
cranial nerve IX.
 Pharyngeal bursa impades passage of ET
Tube , if force is used penetration of mucosa
and create false passage – sepsis and post
op collection of secretions

PHARYNX
 Peritonsilar abscess ( Quinsy ) – nasal
intubation very difficult and dangerous – ET
Tube deflected sharply forwards or impange
and rupture abscess and lead to aspiration
 In unconscious patient following anaesthesia-
tendency of tongue to fall backwards and
obstruct laryngeal opening
 To prevent this – extension of head ,
extension of neck , placing fingers behind
angles of jaw and exerting forward pressure
and oropharyngeal airway

LARYNX
 Extent- lies at C3-C6 in midline of neck ,
formed by cartilaginous skeleton held
together by ligaments ,
 lined by mucous membrane and moved by
muscle
 CARTILAGE- UNPAIRED and PAIRED
 UNPAIRED – Epiglottis , thyroid and cricoid
cartilage
 PAIRED – Arytenoid , corniculate and
cuneiform

Posterior Wall of
Hypopharynx
(Leading to
Esophagus)
Base of
Tongue
Median
Glossoepiglottic
Fold
Superior
Surface of
Epiglottis
Superior
Surface of
Epiglottis
Posterior Wall of
Hypopharynx
(Leading to
Esophagus)
Lateral
Glossoepiglottic
Folds
Median
Glossoepiglottic
Fold
Vallecula

FRAMEWORK OF LARYNX
• Cartilages (hyaline) of the larynx
– Shield-shaped anterosuperior thyroid cartilage
with a midline laryngeal prominence (Adam’s
apple)
– Signet ring–shaped anteroinferior cricoid
cartilage
– Three pairs of small arytenoid, cuneiform, and
corniculate cartilages
• Epiglottis – elastic cartilage that covers the
laryngeal inlet during swallowing

VOCAL LIGAMENTS
• Attach the arytenoid cartilages to the thyroid
cartilage
• Composed of elastic fibers that form
mucosal folds called true vocal cords
– The medial opening between them is the glottis
– They vibrate to produce sound as air rushes up
from the lungs
False vocal cords
Mucosal folds superior to the true vocal
cords
Have no part in sound production

• Speech – intermittent release of expired air
while opening and closing the glottis
• Pitch – determined by the length and tension
of the vocal cords
• Loudness – depends upon the force at which
the air rushes across the vocal cords
• The pharynx resonates, amplifies, and
enhances sound quality
• Sound is “shaped” into language by action of
the pharynx, tongue, soft palate, and lips

• Composed of 3 single
cartilaginous structures:
• Epiglottis-flap, swings down
to meet larynx during
swallowing
• Thyroid-bulk of this forms
larynx
• Cricoid-circular, keeps head
of trachea open

LARYNX
 LIGAMENTS- Intrinsic and extrinsic
 INTRINSIC- Quadrangular membrane
, conus elasticus and thyroepiglottic
ligament
 EXTRINSIC- Thyrohyoid membrane ,
cricothyroid , cricotracheal membrane
, medial and lateral thyrohyoid
ligament
 SYNOVIAL JOINTS- Cricothyroid and
Cricoarytenoid

LARYNX
 MUSCLES- Intrinsic and extrinsic
 Intrinsic-
 Abductors of vocal cords- posterior
cricoarytenoid
 Adductors – lateral cricoarytenoid , oblique
arytenoid , transverse arytenoid
 Tensor – cricothyroid
 Relaxor – thyroarytenoid , vocalis
 Opening of laryngeal inlet – thyroepiglottic
 Closure of laryngeal inlet - aryepiglottic ,
interarytenoid
 Extrinsic- strap muscles and pharyngeal muscles

CARTILAGES OF LARYNX
 THYROID CARTILAGE – longest
laryngeal cartilage , shield like
 formed by embryonic fusion of two
distinct quadrilateral laminae
 in females the sides join at approx 120
degrees and in males closer to 90
degrees , this small thyroid angle
explains the greater laryngeal
prominence in males , the longer vocal
cords and lower pitched voice

CRICOID CARTILAGE
 Anatomical lower limit of larynx
 Thicker and stronger than thyroid
cartilage and represents the only
complete cartilaginous ring in airway ,
thus cautious downward pressure on
cricoid cartilage is possible without
subsequent airway obstruction
 Randsted and colleagues noted that
placment of standard ET Tube through
cricoid cartilage while preventing
mucosal necrosis may be difficult

 Cricothyroid membrane ( trapezoid with
width 27-32 mm and height 5- 12 mm ) –
important surgical landmark – access to
airway by percutaneous or surgical
cricothyroidotomy
 In females width and height of membrane
are smaller than male , anterior
vasculature overlie membrane and pose
risk for hemorrhage
 Presence of transverse cricothyroid artery
traverses upper half of membrane , hence
transverse incision in lower third of
membrane is recommended

INFANT LARYNX
 Size is 1/3 rd of adult , lumen is very narrow
 Position is higher than adult
 Epiglottis lies at C2 and during elevation , it
reaches C1 , so that infant can use nasl
airway for breathing while sucking
 Laryngeal cartilage are softer , more pliable
than adult
 Vocal cords are only 4-4.5 mm long , shorter
than in childhood and adult
 Supraglottic and subglottic mucosa are lax

LARYNX
 During phonation vocal cords meet in
midline
 On inspiration they abduct returning to
midline in expiration
 In order to minimize risk of any trauma
to vocal cords intubation and
extubation should be carried out
during inspiration

VOCAL CORDS PARALYSIS
 Posterior cricoarytenoid – abductor of
vocal cords
 Lateral cricoarytenoid – adducts
arytenoids closing glottis
 Transverse arytenoid – adducts
arytenoid
 Oblique arytenoid – closes glottis
 Aryepiglottic – closes glottis
 Vocalis – relaxes cords
 Thyroarytenoid – relaxes tension cords
 Cricothyroid – tensor of cords

The Vagus
 The vagus nerve has three nuclei
located within the medulla:
◦ 1. The nucleus ambiguus
◦ 2. The dorsal nucleus
◦ 3. The nucleus of the tract of solitarius

 The nucleus ambiguus is the motor
nucleus of the vagus nerve.
 The efferent fibers of the dorsal
(parasympathetic) nucleus innervate the
involuntary muscles of the bronchi,
esophagus, heart, stomach, small
intestine, and part of the large intestine.
 The afferent fibers of the nucleus of the
tract of solitarius carry sensory fibers from
the pharynx, larynx, and esophagus

 The superior laryngeal nerve branches
into internal and external branches.
 The internal superior laryngeal nerve
penetrates the thyrohyoid membrane to
supply sensation to the larynx above the
glottis.
 The external superior laryngeal nerve
innervates the one muscle of the larynx
not innervated by the recurrent laryngeal
nerve, the cricothyroid muscle.

 The right vagus nerve passes anterior to the
subclavian artery and gives off the right
recurrent laryngeal nerve. This loops around
the subclavian and ascends in the tracheo-
esophageal groove, before it enters the
larynx just behind the cricothyroid joint.
 The left vagus does not give off its recurrent
laryngeal nerve until it is in the thorax, where
the left recurrent laryngeal nerve wraps
around the aorta just posterior to the
ligamentum arteriosum. It then ascends back
toward the larynx in the TE groove.

The Laryngeal Musculature
 The intrinsic muscles of the larynx, all
of which are innervated by the
recurrent laryngeal nerve, include the:
◦ Posterior cricoarytenoid - the ONLY
abductor of the vocal folds.
◦ Functions to open the glottis by
rotary motion on the arytenoid
cartilages.
◦ Also tenses cords during phonation.

 Lateral cricoarytenoid - - functions to close
glottis by rotating arytenoids medially.
 Transverse arytenoid - - only unpaired
muscle of the larynx. Functions to
approximate bodies of arytenoids closing
posterior aspect of glottis.
 Oblique arytenoid - - this muscle plus
action of transverse arytenoid function to
close laryngeal introitus during swallowing.

 Thyroarytenoid - - very broad muscle,
usually divided into three parts:
◦ Thyroarytenoideus internus (vocalis) -
adductor and major tensor of free edge of
vocal fold.
◦ Thyroarytenoideus externus - major adductor
of vocal fold
◦ Thyroepiglotticus - shortens vocal ligaments

Anatomy of the Larynx - Motion
 Adductors of the Vocal Folds:

Wegner and Grossman Theory
 “In the absence of cricoarytenoid joint
fixation, an immobile vocal cord in
paramedian position has total pure
unilateral recurrent nerve paralysis,
and an immobile vocal cord in lateral
position has a combined paralysis of
superior and recurrent nerves (the
adductive action of cricothyroid
muscle is lost)”

Causes of vocal cord paralysis
 Malignant : This accounts for 25% of
cases, one half being caused by
carcinoma of lung

 Surgical/Traumatic: (20% cases)
◦ Thyroidectomy
◦ Pneumonectomy
◦ CABG
◦ Penetrating neck or chest trauma.
◦ Post intubation
◦ Whiplash injuries
◦ Posterior fossa surgery

 Neurulogical (5-10%)
◦ Wallenberg syndrome (lateral medullary
stroke)
◦ Syringomyelia
◦ Encephalitis
◦ Parkinsons,
◦ Poliomyelitis
◦ Multiple Sclerosis
◦ Myasthenia Gravis,
◦ Guillian-Barre
◦ Diabetes

 Inflammatory:
◦ Rheumatoid arthritis ( really a "fixed" cord
here)
 Infectious:
◦ Syphilis
◦ Tuberculosis
◦ Thyroiditis
◦ Viral

 Idiopathic (20-25%):
◦ Sarcoidosis,
◦ Lupus
◦ Polyarteritis nodosa
◦ Ortner's syndrome (left atrial hypertrophy).

Intracranial causes
 Head injury
 CVA
 Bulbar
poliomyelitis
 Distinctive
features
 Other
neurological
signs and
symptoms due to
combined
paralysis of soft
palate, pharynx
and larynx

Cranial
 Fracture base of
skull
◦ Juglar foramen
lesions (Glomus
tumours,
Naspharyngeal
Carcinoma)
◦ Skull base
osteomyelitis
 Distinctive features
◦ Other cranial
nerve palsies
(IX,X,XI)
◦ Pharyngeal,
superior and
Recurrent
Laryngeal nerve

Neck
 Thyroidectomy
 Thyroid
Tumours
 Post Cricoid
Carcinoma
 Malignant
Cervical
Lymphnodes
 Distinctive
features
 Superior and
Recurrent
Laryngeal
nerves
involved

Chest
 Bronchogenic
Carcinoma
 Cardiothoracic
Surgery
 Aortic Aneurysm
 Mediastinal
Lymphadenopathy
 Tracheal/Oesophageal
surgery
 Distinctive
feature
◦ Involvement of
Left Recurrent
Laryngeal Nerve

Unilateral Recurrent Laryngeal Nerve
Injury

 This law explains median or
paramedian position of the vocal cords
 It states that ‘In all progressive lesions
of RLN, abductor fibres of the nerve,
which are phylogenetically newer, are
more susceptible and thus first to be
paralysed compared to adductor
fibres’
RLN PARALYSIS -SEMON’S
LAW

RECURRENT LARYNGEAL
NERVE PARALYSIS
(A) UNILATERAL
 Unilateral injury to
recurrent laryngeal nerve
results in ipsilateral
paralysis of all the
intrinsic muscles of
larynx ecxept the
cricothyroid.
 The vocal cords thus
assumes a median or
paramedian position &
doesn’t move laterally
on deep inspiration.
• Clinical features :
- Asymptomatic
- Change in voice
 The voice in unilateral
paralysis gradually
improves due to
compensation by healthy
cord which crosses midline
to meet paralysed one.
• Treatment : Generally no
treatment is required.

(B) BILATERAL (B/L Abductor
paralysis) :
• Position of vocal cords : All the intrinsic
muscles of larynx are paralysed, vocal cords
lie in median or paramedian position due to
unopposed action of cricothyroid muscles.
• Clinical features :
- Dyspnoea
- Stridor

Movement of Vocal cord during
inspiration & expiration

UNILATERAL PARALYSIS OF
SLN
 Paralysis of cricothyroid muscle & ipsilateral anaesthesia of the larynx
above the vocal cord.
Causes :
- Thyroid surgery
- Thyroid Tumors
- Diptheria.
Clinical features :
- Weak voice with decreased pitch
- Anaesthesia of the larynx on one side
- Occassional aspiration.
Laryngeal findings include :
Askew position of glottis - Ant. Comissure is rotated to healthy side.
- Shortening of V.C. with loss of tension & V.C. appears wavy
- Flapping of the paralysed vocal cord – V.C. sags down during inspiration
& bulges up during expiration.

BILATERAL PARALYSIS OF
SLN
 An uncommon condition. Both the cricothyriod muscles are paralysed along with
anaesthesia of upper larynx.
Causes:
- Surgical or accidental trauma
- Diptheria
- Cervical lymphadenopathy
- Neoplastic disease
Clinical features:
- Both V.C. paralysis
- Anaesthesia of larynx
- Cough
- Chocking fits
- Weak & husky voice
Treatment:
- Tracheostomy with a cuffed tube & an oesophageal feeeding tube.
- Epiglottopexy is an operation to close the laryngeal inlet to protect the lungs
from repeated aspiration. It is a reversible precedure.

COMBINED/COMPLETE VOCAL CORD
PARALYSIS
(Recurrent & Superior Laryngeal Nerve
Paralysis)
 UNILATERAL
 Paralysis of all the muscles of the larynx on one side except
interarytenoid which also receives innervation from opposite
side.
Aetiology :
 Thyroid surgery
 Lesions of nucleus ambigus which may lie medulla, post. cranial
fossa, jugular foramen or parapharyngeal space.
Clinical features :
 All the muscles of larynx on one side are paralysed
 V.C. lie in cadeveric position ie. 3.5mm from the midline
 Glottic incompetence results in hoarseness of voice & aspiration
of liquids

 Treatment:
1. Speech therapy
2. Procedures to medialise the cord- Aim is to bring
the paralysed vocal cord towards the midline so that
healthy cord can meet it. This is achieved by :
(a) Injection of teflon paste
(b) Muscle or cartilage implant
(c) Arthrodesis of cricoarytenoid joint
(d) Thyroplasty type I

(B) Bilateral:
• Both recurrent & superior laryngeal nerves on both sides are
paralysed.
• Rare condition.
• Both cords lie in cadaveric position.
• Total anaesthesia of the larynx.
Clinical features :
-Aphonia: As V.C. cords doesn’t meet at all.
-Aspiration: due to incompetent glottis & laryngeal anaesthesia.
-Inability to cough: due to inability of V.C. to meet which results in
retention of secretions in the chest.
-Bronchopneumonia- due to repeated aspirations & retention of
secretions.

Evaluation – Physical Examination
 Complete Head and Neck
Examination
 Flexible Fiberoptic
Laryngoscopy
 90 degree Hopkins Rod-
lens Telescope
 Adequacy of Airway, Gross
Aspiration
 Assess Position of Cords
◦ Median, Paramedian,
Lateral
◦ Posterior Glottic Gap on
Phonation

Evaluation – Unilateral Paralysis
 Manual Compression Test

 manual compression of the thyroid
and cricoid cartilages modifies the
position, shape, and tension of the
vocal folds, adjunctive examinations
used as a means of preoperative
assessment of patients for
medialization laryngoplasty,
 If quality of speech improves with
pressure, patient will benefit from
procedure
 Limitations: older patients, scarred
vocal cords

Treatment:
1. Tracheostomy
2. Epiglottopexy
3. Vocal cord plication
4. Total laryngectomy

 History
 Symptoms:
(a) Change in voice
(b) Hoarseness
(c) Aphonia
(d) Vocal fatigue
(e) Neck pain
(f) Aspiration
(g) Cough
 Past Medical & Surgical History :
 Social History :
 General Examination
 Local Examination :
(a) Examination of larynx & laryngopharynx – IDL, FOL
(b) Neck examination
(c) Cranial nerve examination
 Investigations :
- Nasopharyngolaryngoscopy
- Videostroboscopy
- Chest X-ray PA view
- C.T. with contrast- may evaluate the entire course of
recurrent laryngeal nerve
- MRI

Regulation of air flow
trachea & bronchi held open by cartilaginous rings
smooth muscle in walls of bronchioles & alveolar ducts
sympathetic NS & epinephrine  relaxation ( receptors)  air flow
leukotrienes
(inflammation & allergens  leukotrienes  mucus & constriction)
Protection
mucus escalator (goblet cells in bronchioles & ciliated epithelium)
inhibited by cigarette smoke
Warming & humidifying inspired air
expired air is 37 & 100% humidity (loss of ~400 ml pure water/day)
Phonation
larynx & vocal cords

TRACHEA
 It is a tube made up of cartilage and enclosed
posteriorly by tracheal muscle and lined
interiorly by ciliated columnar epithelium . It is
about 18mm in diameter and 10-11 cm in
length in adult
 Extent-lower part if larynx ( C6 ) to T5 , where it
divides into left and right bronchi
 TRACHEOBRONCHIAL TREE- tracheal
bifurcation occurs approx at a distance of 25
cm from upper incisor teeth in adults . Carina is
a sharp shining ridge formed after bifurcation of
trachea into 2 principal bronchus

 Trachea moves with respiration
 On deep inspiration carina can
descend as much as 2.5 cm
 Extension of head and neck – ideal
position to maintain airway in
anaesthetised patient – can increase
length of trachea by 20-30 %

RIGHT BRONCHIAL TREE
 Right main bronchus is wider and
shorter than left , being only 2.5 cm
long
 As it is more nearly vertical than left
main bronchus there is much greater
tendency for either endotracheal tube
or suction catheters to enter lumen
 In small children under age of 3 years
angulation of two main bronchi at
carina is equal on both sides

 In an event of ET Tube being inserted too far
further complication is that bevelled end of
tube ( as usually cut ) may become blocked
off by its lying against mucosa of medial wall
of main bronchus
 Short length of this bronchus makes the
lumen difficult to occlude when this is
required in thoracic anaesthesia
 Patency of middle lobe bronchus is
particularly vulnerable to glandular swelling
because it is closely related to right
tracheobronchial group of glands

 Posterior segment of upper lobe ,
together with apical segment of lower
lobe is one of the commonest site for
development of lung abscess
 When patient is lying wholly or partly
on his side , inhaled material tends to
gravitate into lateral portion of
posyerior segment of upper lobe –
particularly right side
 If patient lies on his back- apical
segment of lower lobe
 Incidence of lung abscess is twice as
high in upper lobes as in lower lobes

LEFT BRONCHIAL TREE
 It is narrower than right and is nearly 5
cm long
 Presence of 5 cm of bronchial lumen
uninturrupted by any branching makes
left main bronchus particularly suitable
for intubation and blocking during
thoracic aneasthesia
 It terminates at origin of upper lobe
bronchus thus becoming main stem to
lower lobe

LUNGS
• Light, soft, spongy
• Conical in shape, apex, base, costal surface,
medial surface, hilus. Note various
impressions
• Right lung
– Three lobes; superior, middle and inferior
– Oblique and horizontal fissure
• Left Lung
– Two lobes; superior and inferior also Lingula and
Cardiac notch, oblique fissure

AIRWAY
• Primary Brochi
• One to each lung – continuation of trachea
– Right bronchus is wider and shorter 2.5 cm as
opposed to 5 cm and branches from the trachea at
a greater angle
• Secondary bronchi – one to each lobe, three
in right, two in left
• Tertiary – one to each bronchopulmonary
segment – approximately 10 per lung
• All of the above are hyaline cartilage with no
ability to change diameter

BRONCHIOLES
• Gas Exchange
• Pulmonary arteries carry deoxygenated
blood to aleoli
• Gas exchange occurs via diffusion
through the capillary beds
• Returned to heart via pulmonary veins

INNERVATION
• Pleura via intercostal (thoracic) nerves
• Tracheobronchial tree
• Parasympathetic via CN X efferent
function = broncho-constriction via
smooth mm., also to epithelial cells in
trachea; afferent = responsible for
cough reflex
• Sympathetic from T1-T5 efferent =
brocho-dilation

BLOOD SUPPLY
• Lungs do not receive any vascular
supply from the pulmonary vessels
(pulmonary aa. or veins)
• Blood delivered to lung tissue via the
bronchiole arteries
• Vessels evolve from aortic arch
• Travel along the bronchial tree

 Carina acts a anchor for double lumen
tube
 Right principal bronchus is wider
shorter and more vertical than left
bronchus
 There is much greater tendency for
foreign bodies , ET Tube and suction
to enter right principal bronchus

 Each principal bronchus enters lung
through hilum and divides into secondary (
lobar ) bronchi , one for each lobe of lungs (
3 on right and 2 on left ) each lobar bronchi
divide into tertiary( segmental bronchi) ,
one for each bronchopulmonary segment
 Tertiary ( segmental ) bronchi divides
repeatedly to form very small branches
called terminal bronchioles and still smaller
branches called respiratory bronchioles

 From proximal part of terminal bronchioles
gas exchange begins and extends throughout
succeding generations of airways to alveoli.
corresponds to anatomical dead space and
alveolar dead space respectively.
 Each respiratory bronchiole aeriates small
part of lung known as pulmonary unit or
terminal respiratory unit / acinus
 Respiarotry bronchiole ends in microscopic
passages : alveolar ducts containing 2 or
more pulmonary alveoli , atria and air
saccules

ALVEOLAR STRUCTURE
Type I epithelial cells
thin, flat; gas exchange
Type II epithelial cells
secrete pulmonary surfactant  pulmonary compliance
Pulmonary capillaries
completely surround each alveolus; “sheet” of blood
Interstitial space
diffusion distance for O2 & CO2 is less than diameter of
red blood cell
Elastic fibers
secreted by fibroblasts into pulmonary interstitial space
tend to collapse lung

 Nervous or neural mechanism
 Chemical mechanism
Nervous Mechanism:
 It involves respiratory centers, afferent and efferent
nerves
Respiratory centers: The centres in the medulla
oblongata and pons that collects sensory information
about the level of oxygen and carbon dioxide in the
blood and determines the signals to be sent to the
respiratory muscles.
 Stimulation of these respiratory muscles provide
respiratory movements which leads to alveolar
ventilation.
Respiratory centers are situated in the reticular
formation of the brainstem and depending upon the
situation in brainstem, the respiratory centers are
classified into two groups:
1. Medullary centers
2. Pontine centers

 Medullary Centers:
A. Inspiratory center
B. Expiratory center
 Pontine Centers:
A. Pneumotaxic center
B. Apneustic center

Anatomy of airway

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