anatomy of larynx and its anaesthetic importance
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ANATOMY OF LARYNX ANATOMY OF LARYNX
AND ITS ANAESTHETIC AND ITS ANAESTHETIC
IMPORTANCE IMPORTANCE
Presented by Presented by
Dr Sindhu SapruDr Sindhu Sapru
Moderator Moderator
Dr. S.P MeenaDr. S.P Meena
LarynxLarynx
An air passage, a sphincter and an An air passage, a sphincter and an
organ of phonation. organ of phonation.
Extends from root of tongue to trachea Extends from root of tongue to trachea
At RestAt Rest– Lies opposite 3Lies opposite 3rdrd-6-6thth cervical vertebra in cervical vertebra in
adult male adult male – Some what higher in children( 2Some what higher in children( 2ndnd and 3 and 3rdrd
cervical vertebrae) and femalescervical vertebrae) and females
Upto puberty – Male and female larynx Upto puberty – Male and female larynx
similar in size after that male larynx similar in size after that male larynx
enlarges considerably and continue until enlarges considerably and continue until
40 years of age. 40 years of age.
Difference between male and Difference between male and female larynxfemale larynx
MaleMale FemaleFemale
Length Length 44 mm44 mm 36 mm36 mm
Transverse Transverse diameterdiameter
43 mm43 mm 41 mm41 mm
Sagittal diameterSagittal diameter 36 mm36 mm 26 mm26 mm
EmbryologyEmbryology Internal lining of larynx Internal lining of larynx
EndodermEndoderm Cartilage and muscleCartilage and muscle
Mesenchyme of 4Mesenchyme of 4thth and 6 and 6thth Pharyngeal arches Pharyngeal arches Rapid proliferation of mesenchymeRapid proliferation of mesenchyme
Change in laryngeal orifice from sagittal slit to T-shaped Change in laryngeal orifice from sagittal slit to T-shaped opening opening
Transforms into thyroid, cricoid and arytenoid cartilages Transforms into thyroid, cricoid and arytenoid cartilages Rapid proliferation of epithelium Rapid proliferation of epithelium
Temporary occlusion of lumen Temporary occlusion of lumen Vacuolization and recanalization Vacuolization and recanalization Formation of laryngeal ventricles Formation of laryngeal ventricles False and true vocal cords. False and true vocal cords.
All laryngeal muscles innervated All laryngeal muscles innervated
by 10by 10thth cranial nerve cranial nerve
Superior laryngeal N. innervate Superior laryngeal N. innervate
derivatives of 4derivatives of 4thth pharyngeal arch pharyngeal arch
Recurrent laryngeal N. innervate Recurrent laryngeal N. innervate
derivatives of 6derivatives of 6thth pharyngeal arch pharyngeal arch
Skeleton of Larynx Skeleton of Larynx
Series of cartilages interconnected by Series of cartilages interconnected by
ligaments and fibrous membrane and ligaments and fibrous membrane and
moved by number of muscles. moved by number of muscles. Laryngeal Cartilages Laryngeal Cartilages
Single Single PairedPaired Cricoid Cricoid Thyroid Thyroid Epiglottis Epiglottis
CorniculateCorniculate Arytenoid Arytenoid Cuneiform Cuneiform Tritate Tritate
Corniculate, cuneiform, tritate, epiglottis and Corniculate, cuneiform, tritate, epiglottis and
apices of arytenoid are composed of elastic apices of arytenoid are composed of elastic
fibrocartilage with little tendancy to calcify. fibrocartilage with little tendancy to calcify.
Thyroid, cricoid and greater part of arytenoid Thyroid, cricoid and greater part of arytenoid
composed of hyaline cartilage and may undergo composed of hyaline cartilage and may undergo
mottled calcification with advancing age. mottled calcification with advancing age.
EPIGLOTTIS
EpiglottisEpiglottis
Thin leaf like plate of elastic fibrocartilage Thin leaf like plate of elastic fibrocartilage
projects obliquely upward behind the projects obliquely upward behind the
tongue and hyoid body and in front of tongue and hyoid body and in front of
laryngeal inlet laryngeal inlet Free end Free end Attached partAttached part Broad and Broad and
notched in notched in
midline midline
Long and narrow Long and narrow
Connected to Connected to
elastic elastic
thyroepiglottic thyroepiglottic
ligament ligament Sides: Attached to arytenoids by aryepiglottic folds
Anterior surface : Covered by mucosa (non
keratinised stratified squamous) reflect to
tongue as median glossoepiglottic fold and
pharynx as two lateral glossoepiglottic fold
Post surfacePost surface : Covered by ciliated : Covered by ciliated
respiratory mucosa. Tubercle of the respiratory mucosa. Tubercle of the
epiglottis.epiglottis.
Valleculae Valleculae : : Depression on each side of median Depression on each side of median
fold. Common sites for impaction of sharp fold. Common sites for impaction of sharp
swallowed objects.swallowed objects.
Pitted by small mucous glands Perforated by Pitted by small mucous glands Perforated by
branches of internal laryngeal nerve and fibrous branches of internal laryngeal nerve and fibrous
tissue, to be continue with pre – epiglottic space. tissue, to be continue with pre – epiglottic space.
Function of epiglottisFunction of epiglottis During DeglutitionDuring Deglutition
Hyoid bone move upward and forward Hyoid bone move upward and forward Epiglottis is bent posteriorly on laryngeal inlet Epiglottis is bent posteriorly on laryngeal inlet Food bolus slips over its ant surface to reach in piriform Food bolus slips over its ant surface to reach in piriform
fossa which constitute lateral food passagefossa which constitute lateral food passage
Sense of tasteSense of taste
Assist in phonationAssist in phonation
Gag reflexGag reflex
Prevent aspiration of food into the tracheaPrevent aspiration of food into the trachea
Thyroid cartilage Thyroid cartilage
Largest of laryngeal cartilage Largest of laryngeal cartilage Consist of 2 quadrilateral Consist of 2 quadrilateral
laminae, fuse along their laminae, fuse along their inferior two third anteriorly inferior two third anteriorly to form laryngeal prominence to form laryngeal prominence
Above laminae separated by Above laminae separated by V shaped superior thyroid V shaped superior thyroid notch or incisurenotch or incisure
Posteriorly – Lamina diverge Posteriorly – Lamina diverge as slender horns as slender horns Superior cornua Superior cornua Inferior cornua Inferior cornua
Internal surface and lamina – SmoothInternal surface and lamina – Smooth
Angle between laminae provide Angle between laminae provide
attachment to:attachment to:
Thyroepiglottic ligamentThyroepiglottic ligament
paired (vestibular and vocal ligaments) paired (vestibular and vocal ligaments)
ThyoarytenoidThyoarytenoid
thyroepiglottic and vocal muscle thyroepiglottic and vocal muscle
Anteriorly – connected to cricoid cartilage Anteriorly – connected to cricoid cartilage
by anterior (median) cricothyroid by anterior (median) cricothyroid
ligament (thickened portion of ligament (thickened portion of
cricothyroid membrane)cricothyroid membrane)
Thyroid cont…Thyroid cont…
Ant. Border of laminae fuse at Ant. Border of laminae fuse at
angle of 90º in males and 120º in angle of 90º in males and 120º in
female. female.
Shallower angle in men Shallower angle in men
– Large laryngeal prominence( Adams apple)Large laryngeal prominence( Adams apple)
– Greater length of vocal cordsGreater length of vocal cords
– Deeper pitchDeeper pitch
The oblique line provide the attachment of the :1.Thyrohyoid 2.Inferior constrictor of the pharynx
Cricoid cartilage Cricoid cartilage Attached below to trachea and articulate Attached below to trachea and articulate
with thyroid cartilage and two arytenoid with thyroid cartilage and two arytenoid
cartilage by synovial joints. cartilage by synovial joints.
Only laryngeal cartilage to form a complete Only laryngeal cartilage to form a complete
ringring
Smaller but thicker & stronger than thyroid Smaller but thicker & stronger than thyroid
Arch Lamina• Ant. narrow, curved
•Cricothyroid and deeper cricopharyngeous attached to ext. aspect
•Posteriorly broad flattened
•Bears median vertical ridge
•Fasciculi of longitudinal layer of oesophageal muscle attached by a tendon to upper part of ridge
JointsJoints
Cricothyroid Cricothyroid
Cricoarytenoid Cricoarytenoid
Arytenocorniculate Arytenocorniculate
All are synovial joints All are synovial joints
Ligaments and Membranes Ligaments and Membranes Extrinsic ligament and membranes Extrinsic ligament and membranes
Thyrohyoid membrane Thyrohyoid membrane
– Extends from superior border and superior cornua of Extends from superior border and superior cornua of
thyroid to superior margin of body and greater cornua of thyroid to superior margin of body and greater cornua of
hyoid hyoid
– Thicker part is median thyrohyoid ligament Thicker part is median thyrohyoid ligament
– Pierced by the internal laryngeal nerve and superior Pierced by the internal laryngeal nerve and superior
laryngeal vesselslaryngeal vessels
Hyoepiglottic ligamentHyoepiglottic ligament
Cricotracheal ligamentCricotracheal ligament
Thyroepiglottic ligamentThyroepiglottic ligament
Intrinsic ligaments and membranes Intrinsic ligaments and membranes
Part of the Part of the fibroelastic membrane of the larynx :-fibroelastic membrane of the larynx :-
Quadrate membrane- Quadrate membrane- part above the sinus. part above the sinus.
From the arytenoid cartilage to epiglottis.From the arytenoid cartilage to epiglottis.
lower free border – lower free border – vestibular ligament vestibular ligament which which
underlies the vestibular fold (false cord)underlies the vestibular fold (false cord)
upper border – upper border – aryepiglottic foldaryepiglottic fold
Conus elasticus(crico vocal membrane) : Conus elasticus(crico vocal membrane) :
ant part – thick known as ant part – thick known as criothyroid ligamentcriothyroid ligament
upper free border – upper free border – vocal foldvocal fold
Laryngeal cavity Laryngeal cavity
Extends from laryngeal inlet down to lower Extends from laryngeal inlet down to lower
border of cricoid cartilage where it border of cricoid cartilage where it
continues into tracheacontinues into trachea
By paired upper and lower mucosal fold By paired upper and lower mucosal fold
projecting into lumen laryngeal cavity is projecting into lumen laryngeal cavity is
divided intodivided into
Upper(Vestibule) Middle( sinus of larynx)
Lower(infraglottic)
Upper fold : Vestibular fold guarding rima Upper fold : Vestibular fold guarding rima vestibuli. vestibuli.
Lower fold – Vocal fold guarding rima glottidis Lower fold – Vocal fold guarding rima glottidis
Laryngeal inlet or aditius- Laryngeal inlet or aditius- lookslooks backwards backwards
and upwards.and upwards.
Anterior- epiglottisAnterior- epiglottis
Posterior- interarytenoid fold of mucous Posterior- interarytenoid fold of mucous
membranemembrane
Each side- aryepiglottic foldEach side- aryepiglottic fold
Saccule of larynx- Saccule of larynx- Anterior part of the sinus is Anterior part of the sinus is
prolonged upwards as a divericulum between the prolonged upwards as a divericulum between the
vestibular fold and lamina of thyroid cartilage. vestibular fold and lamina of thyroid cartilage.
Vocal Cords and ligamentsVocal Cords and ligaments
Free thickened upper edge of cricovocal membrane Free thickened upper edge of cricovocal membrane
– vocal ligament – vocal ligament
When covered by mucosa – vocal fold ( true vocal When covered by mucosa – vocal fold ( true vocal
cord )cord )
Reinke’s EdemaReinke’s Edema
Any tissue swelling below vocal cords exaggerates Any tissue swelling below vocal cords exaggerates
potential space deep to mucosa causing accumulation of potential space deep to mucosa causing accumulation of
ECF and flabby swelling of vocal cord. ECF and flabby swelling of vocal cord.
Diff. position of vocal cords and Diff. position of vocal cords and arytenoid cartilages arytenoid cartilages
Muscle of LarynxMuscle of Larynx
Extrinsic : Connect larynx to neighbouring structures Extrinsic : Connect larynx to neighbouring structures
Infrahyoid strap muscles i.e. thyrohyoid, Infrahyoid strap muscles i.e. thyrohyoid,
sternothyroid, sternohyoid, inf. Constrictor of pharynx sternothyroid, sternohyoid, inf. Constrictor of pharynx
Intrinsic muscle Intrinsic muscle
– Oblique arytenoid and aryepiglottic muscleOblique arytenoid and aryepiglottic muscle
– Transverse (inter arytenoid)Transverse (inter arytenoid)
– Posterior cricorytenoidPosterior cricorytenoid
– Lateral cricoarytenoid Lateral cricoarytenoid
– Cricothyroid Cricothyroid
Muscle Actions Muscle Actions Elevation of larynx- thyrohyoid, mylohyoidElevation of larynx- thyrohyoid, mylohyoid
Depression of larynx- sternothyroid, sternohyoidDepression of larynx- sternothyroid, sternohyoid
Abductors – Posterior cricoarytenoid Abductors – Posterior cricoarytenoid
Adductor - Lateral cricoarytenoid, interarytenoid Adductor - Lateral cricoarytenoid, interarytenoid
Sphincter to vestibuli – Aryepiglottics, Sphincter to vestibuli – Aryepiglottics,
thyroepiglotticsthyroepiglottics
Regulation of cord tension Regulation of cord tension
– Cricothyroid (Tensor)Cricothyroid (Tensor)
– Thyroarytenoid – (Relaxors)Thyroarytenoid – (Relaxors)
– Vocalis (fine adjustment) Vocalis (fine adjustment)
Infant Larynx Infant Larynx 1/3 size of adult, though it is proportionately larger. 1/3 size of adult, though it is proportionately larger.
Cavity – short and funnel shapedCavity – short and funnel shaped
Lumen is disproportionately narrowerLumen is disproportionately narrower
Lies high in neck Lies high in neck
At rest – Upper border of epiglottis at 2At rest – Upper border of epiglottis at 2ndnd / 3 / 3rdrd cervical cervical
vertebrae, on elevation – reach upto 1vertebrae, on elevation – reach upto 1stst cervical vertebrae cervical vertebrae
This high position – Ability to use nasal airway to breathe This high position – Ability to use nasal airway to breathe
and suckling and suckling
Epiglottis – Epiglottis –
X shaped with furled petiole laryngeal cartilages are X shaped with furled petiole laryngeal cartilages are
softer and more pliable softer and more pliable
Predispose to airway collapse in inspirationPredispose to airway collapse in inspiration
Thyroid cartilage – Thyroid cartilage – Shorter and broader Shorter and broader Cricoid cartilage – Cricoid cartilage – Same shape Same shape Vocal cords – Vocal cords – 4-4.5 mm long, relatively short4-4.5 mm long, relatively short Narrowest part of larynx – Subglottis Narrowest part of larynx – Subglottis
One size smaller ETtube should be ready along with the One size smaller ETtube should be ready along with the ETtube calculated for the ageETtube calculated for the age. .
Unlike adults, neonatal subglottic cavity Unlike adults, neonatal subglottic cavity extends posteriorly as well a inferiorly which is extends posteriorly as well a inferiorly which is important to consider when passing ET tube. important to consider when passing ET tube.
Blood Supply Blood Supply
– Mainly from Superior and Inferior laryngeal Mainly from Superior and Inferior laryngeal
arteries. arteries.
Superior laryngeal ASuperior laryngeal A
Branch of sup. Thyroid A – Br. Of ext. carotid artery Branch of sup. Thyroid A – Br. Of ext. carotid artery
In 15% cases directly from ext. carotid A.In 15% cases directly from ext. carotid A.
Run’s down towards larynx with internal branch of sup. Run’s down towards larynx with internal branch of sup.
laryngeal N. lying above it. Enter the larynx by penetrating laryngeal N. lying above it. Enter the larynx by penetrating
thyrohyoid membrane. thyrohyoid membrane.
Supplies larynx above the vocal fold.Supplies larynx above the vocal fold.
Inferior laryngeal A Inferior laryngeal A
Smaller than sup. Laryngeal ASmaller than sup. Laryngeal A
Br. Of inf. Thyroid A – Arises from thyrocervical trunk of Br. Of inf. Thyroid A – Arises from thyrocervical trunk of
subclavin A. subclavin A.
Ascends on trachea with recurrent laryngeal NAscends on trachea with recurrent laryngeal N
Enter larynx at lower border of inf. Constrictor muscles.Enter larynx at lower border of inf. Constrictor muscles.
Supplies larynx below vocal folds. Supplies larynx below vocal folds.
Cricothyroid A Cricothyroid A – Arises from sup. Thyroid A. – Arises from sup. Thyroid A.
Venous supply Venous supply
– Sup. and inf. Laryngeal veinSup. and inf. Laryngeal vein
– Sup. laryngeal vein – sup thyroid V – Int. Sup. laryngeal vein – sup thyroid V – Int.
Jugular V. Jugular V.
– Inf. Laryngeal vein – Inf. Thyroid V – Lt. Inf. Laryngeal vein – Inf. Thyroid V – Lt.
brachiocephalic vein brachiocephalic vein
Lymphatic supply Lymphatic supply
Above vocal cords Above vocal cords
Upper deep cervical lymph nodes Upper deep cervical lymph nodes
Below vocal cords Below vocal cords
Some into Some into Prelaryngeal (delphian)Prelaryngeal (delphian)
Pretrachial Pretrachial
Other Other Lower deep cervical lymph nodes Lower deep cervical lymph nodes
Nerve Innervation Nerve Innervation EpiglottisEpiglottis
– Pharyngeal surface -: Pharyngeal surface -:
Glossopharyngeal nerveGlossopharyngeal nerve
– Laryngeal surface -: Laryngeal surface -: Vagus nerveVagus nerve
Stimulation of laryngeal side of epiglottis during
laryngoscopy with Miller’s blade may produce
vagally related reactions –
Laryngospasm, Bradycardia, hypertension
Rest of larynx
SensorySensory
Above vocal cords – Internal branch of sup Above vocal cords – Internal branch of sup
laryngeal N. laryngeal N.
Below vocal cords - Recurrent laryngeal nerveBelow vocal cords - Recurrent laryngeal nerve
MotorMotor
All muscles of larynx are supplied by recurrent All muscles of larynx are supplied by recurrent
laryngeal nerve except laryngeal nerve except cricothyroid cricothyroid which is which is
supplied by supplied by external branch of superior laryngeal external branch of superior laryngeal
nervenerve..
Sup. Laryngeal N. : Arises form middle Sup. Laryngeal N. : Arises form middle and inf. and inf.
Vagal ganglion Vagal ganglion
Int. laryngeal N.
Ext. laryngeal N
• Pierces thyrohyoid membrane
• Sup. Br. – Mucosa of piriform fossa
• Middle Br – Musoca of ventricle
• Inf. Br. Mucosa of subglottic cavity
• Continue downwad on lat.
Surface of inf. Constrictor
• Close relationship to Sup.
Thyroid Artery where art is
clamped during thyroid
lobectomy
Recurrent laryngeal nerveRecurrent laryngeal nerve
Close and variable relationship to inf. Close and variable relationship to inf.
thyroid arterythyroid artery
May pass in front or behind or May pass in front or behind or
parallel to artery parallel to artery
Ant. Br. – MotorAnt. Br. – Motor
Post Br. – Sensory Post Br. – Sensory
Rt. Side Rt. Side – Leaves the vagus, at level of Rt. Subclavian A. then Leaves the vagus, at level of Rt. Subclavian A. then
loops under the art & ascend to larynx in loops under the art & ascend to larynx in trancheoesophageal groovetrancheoesophageal groove
Left side Left side – Originates from vagus at level of aortic arch nerve Originates from vagus at level of aortic arch nerve
passes under the arch to reach tracheoesphageal passes under the arch to reach tracheoesphageal groove.groove.
Unusual anomalyUnusual anomaly
Non recurrent laryngeal nerveNon recurrent laryngeal nerve
Freg. 0.3 – 1%Freg. 0.3 – 1%
Only Rt. Side affected Only Rt. Side affected
Always associated with abnormal origin of Rt. Always associated with abnormal origin of Rt.
Subclavian A from aortic arch on left side. Subclavian A from aortic arch on left side.
CLINICAL IMPORTANCECLINICAL IMPORTANCE
Subglottic StenosisSubglottic Stenosis
Congenital malformation of Congenital malformation of
cricoid cartilage resulting in cricoid cartilage resulting in
severe narrowing of subglottic severe narrowing of subglottic
airway and respiratory airway and respiratory
obstruction.obstruction.
Other reasonsOther reasons
TraumaTrauma
Scarring after prolonged endotracheal Scarring after prolonged endotracheal
intubation (in premature babies and in intubation (in premature babies and in
I.C.U.)I.C.U.)
LaryngocoeleLaryngocoeleObstruction of ventricular aditus by Obstruction of ventricular aditus by
inflammation, inflammation, scarring, tumor scarring, tumor
Mucous filled cavity (laryngocoele) Mucous filled cavity (laryngocoele)
Expansion Expansion
Into paraglottic Into paraglottic space and space and
aryepiglottic space aryepiglottic space (internal (internal
laryngocoele)laryngocoele)
Through thyrohyoid Through thyrohyoid membrane to present as membrane to present as a lump in neck (external a lump in neck (external
laryngocoele)laryngocoele)
Injuries of the laryngeal nervesInjuries of the laryngeal nerves Ext. br. of superior laryngeal nerve- Ext. br. of superior laryngeal nerve-
descends over the inferior constrictor muscle of the
pharynx immediately deep to the superior thyroid
artery and vein as these pass to the superior pole of
the gland; at this site the nerve may be damaged in
securing these vessels.
Paralysis of cricothyroid- hoarseness which is
compensatory
Causes of rec. laryngeal nerve injuryCauses of rec. laryngeal nerve injury Close relation to the inferior thyroid artery. On the
left side more likely to lie posterior to the artery.
Thyroidectomy Thyroidectomy
Malignant and benign enlargement of thyroid gland Malignant and benign enlargement of thyroid gland
Enlarged lymph nodesEnlarged lymph nodes
Cervical trauma Cervical trauma
Left RLN : May be involved in thoracic causesLeft RLN : May be involved in thoracic causes
Malignant tumor of lung, oesophagus, malignant node Malignant tumor of lung, oesophagus, malignant node
Mitral stenosis Mitral stenosis
Compression between Lt. pulmonary artery Compression between Lt. pulmonary artery
(pushed forward by greately enlarged Lt. Atrium) (pushed forward by greately enlarged Lt. Atrium)
and aortic archand aortic arch
Following ligation of PDAFollowing ligation of PDA
U/L complete paralysis of Rec. L.N. U/L complete paralysis of Rec. L.N. Asymptomatic or having hoarse voice Asymptomatic or having hoarse voice Hoarseness may be permanent or become less Hoarseness may be permanent or become less
severe with time as healthy cord hyper-adduct severe with time as healthy cord hyper-adduct and appose paralysed cord.and appose paralysed cord.
No risk of aspiration No risk of aspiration
B/L R.L.N. Paralysis B/L R.L.N. Paralysis Complete loss of vocal powerComplete loss of vocal power Vocal folds in cadaveric position (in btw Vocal folds in cadaveric position (in btw
adduction and abduction)adduction and abduction) Valve like obstruction(esp during inspiration) -Valve like obstruction(esp during inspiration) -
dyspnea & marked inspiratory stridor.dyspnea & marked inspiratory stridor.
Respiratory obstruction after thyroidectomy- Respiratory obstruction after thyroidectomy- direct trauma to the tracheal cartilages (especially in
carcinoma of the thyroid) causing tracheomalacia. Haemorrhage into the neck deep to the investing fascia,
causing external pressure on the trachea.HHaemorrhage into an intact gland is more likely to obstruct the airway by into an intact gland is more likely to obstruct the airway by producing laryngeal oedema than by direct compression.producing laryngeal oedema than by direct compression.
If the tracheal cartilages have not been damaged,very unusual for a benign enlarged thyroid to compress the trachea to an extent that prevents tracheal intubation. The trachea invariably straightens and dilates during intubation.
Laryngoscopy within 24 h of thyroidectomy often reveals some degree of oedema of the false cords, presumably as a result of external laryngeal trauma during the operation and damage to venous and lymphatic drainage channels.
CRICOTHYROTOMYCRICOTHYROTOMY
‘‘Surgical’ airway via the cricothyroid Surgical’ airway via the cricothyroid membrane in acute emergency when membrane in acute emergency when obsruction at or above the larynx not obsruction at or above the larynx not relieved.relieved.
Patient positon: supine and the neck in the Patient positon: supine and the neck in the neutral position or (in the absence of neutral position or (in the absence of cervical spine injury) in extensioncervical spine injury) in extension
Cricothyrotomy is relatively easy to perform and Cricothyrotomy is relatively easy to perform and should (in theory at least) be associated with should (in theory at least) be associated with minimal blood loss, as the cricothyroid membrane minimal blood loss, as the cricothyroid membrane is thought to be largely avascularis thought to be largely avascular
Laryngoscopic anatomy Laryngoscopic anatomy To view larynx To view larynx
– Mouth, oropharynx and larynx must be Mouth, oropharynx and larynx must be
in one planein one plane
Flexion at the
atlantoaxial
joint
Like moving the head forward to take 1st sip from a glass of water full to the brim.
Extension at atlanto
occipital joint .
sniffing position
Structures Visible Structures Visible
Base of tongueBase of tongue
ValleculaeValleculae
Ant. Surface of epiglottis Ant. Surface of epiglottis
Laryngeal aditus Laryngeal aditus
Front - post. Aspect of epiglottis Front - post. Aspect of epiglottis
Aryepiglotic fold on each side post. Medially Aryepiglotic fold on each side post. Medially
Vocal CordsVocal Cords
Pale, glistening, ribbon, extending from angle of thyroid Pale, glistening, ribbon, extending from angle of thyroid
cartilage backwards to vocal process of arytenoids cartilage backwards to vocal process of arytenoids
AIRWAY BLOCKSAIRWAY BLOCKS General Indications :
Before anesthetic induction in patients with airway compromise, trauma to the upper airway, or cervical instability.
To abolish or blunt reflexes such as laryngospasm, coughing, and other undesirable cardiovascular reflexes that often occur during procedures that involve manipulation of the airway (awake laryngoscopy, nasal intubation, and fiberoptic intubation).
To provide patient comfort and airway anesthesia during the performance of these procedures.
SUPERIOR LARYNGEAL NERVE SUPERIOR LARYNGEAL NERVE BLOCKBLOCK
Indications: To block the internal (sensory) branch of the SLN, resulting in abolition of the gag reflex or hemodynamic responses to laryngoscopy or bronchoscopy.
Drugs: 2-4 ml of Lidocaine 1% or 2% lidocaine, with or without epinephrine.
Patient Position: Supine, with head slightly extended.Patient Position: Supine, with head slightly extended.
GLOSSOPHARYNGEAL NERVE GLOSSOPHARYNGEAL NERVE BLOCKBLOCK
When topical techniques are not completely effective When topical techniques are not completely effective in obliterating the gag reflex. This block can be in obliterating the gag reflex. This block can be performed after the mouth and oropharynx are performed after the mouth and oropharynx are adequately anesthetized. Branches of this nerve are adequately anesthetized. Branches of this nerve are most easily accessed as they transverse the most easily accessed as they transverse the palatoglossal foldspalatoglossal folds
A posterior approach A posterior approach (*often used for (*often used for tonsillectomy), may tonsillectomy), may be difficult, in be difficult, in visualizing the site visualizing the site for needle insertion, for needle insertion, which is behind the which is behind the palatopharyngeal palatopharyngeal arch (where the arch (where the nerve is in close nerve is in close proximity to the proximity to the carotid artery). There carotid artery). There is risk for arterial is risk for arterial injection and injection and bleedingbleeding
RECURRENT LARYNGEAL NERVE RECURRENT LARYNGEAL NERVE BLOCK( TRANSTRACHEAL/ BLOCK( TRANSTRACHEAL/ TRANSLARYNGEAL)TRANSLARYNGEAL) IndicationsIndications: : Transtracheal injection performed to block
the recurrent laryngeal nerve for awake laryngoscopy, fiberoptic and/or retrograde intubation. Abolition of the gag reflex or hemodynamic responses to laryngoscopy or bronchoscopy. Used to help avoid Valsalva-like straining that may follow other "awake" intubations (patient is sedated and spontaneously ventilating).
Drugs: Drugs: Most often, 3-4 ml of Lidocaine 4 % is used. Also, 1% or 2% lidocaine, with or without epinephrine.
Patient PositionPatient Position: Supine, with neck hyperextended (or pillow removed and extended).
Placement of fingers to identify the midline of the cricothyroid membrane
Placement of needle
Transtracheal spread of local anaesthetic with coughing
Thank You.Thank You.