Download Right recurrent laryngeal nerve

Laryngology
Embryology
Anatomy
Physiology
Embryology
• Fish gills and Branchial clefts-1st to 6th
• Windpipe, trachea-glottis, framework
• Swim bladder -> lungs
Halsey-VS Conf-5/7/09
Embryology
Halsey-VS Conf-5/7/09
Embryology of Larynx
Halsey-VS Conf-5/7/09
Comparative Anatomy
• Crossroads of breathing, swallowing and
vocalizing
• Larynx is often positioned high in neck
even in non-human primates
• Infant humans retain this until descent
• Adult human descends
Halsey-VS Conf-5/7/09
Malformations
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Atresia
Laryngomalacia
Congenital Subglottic stenosis
Laryngeal webs
Branchial Clefts and Cysts
Halsey-VS Conf-5/7/09
Anomalies
Halsey-VS Conf-5/7/09
Anomalies
Halsey-VS Conf-5/7/09
Subglottic Stenosis
Halsey-VS Conf-5/7/09
Physiology
• Descent of larynx occurred
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Two stages
 Thyroid in relation to hyoid to prevent aspiration
 Descent of hyoid in neck in speech development
• Combined respiration and deglutition
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Better in infant
Poor in adult
• Olfaction – consider epiglottis role
Halsey-VS Conf-5/7/09
Anatomy
• Pharynx
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Naso
Oro
Hypo
• Larynx
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Supraglottic
Glottic
Subglottic
• Trachea and Lungs
• Esophagus
Halsey-VS Conf-5/7/09
Protection Levels
• First level-Epiglottis, aryepiglottic folds &
arytenoids
• Second level-False vocal folds
• Third level-True vocal folds
• Anomalies of any of this structures lead to
aspiration and swallowing dysfunction
• Symptoms-coughing, choking and gagging
episodes, stasis of secretion, and recurrent
pneumonia
Halsey-VS Conf-5/7/09
Laryngopharynx
Halsey-VS Conf-5/7/09
Laryngeal Framework
• Cricoid cartilage
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Only complete cartilaginous ring in the airway
Strongest of the laryngeal cartilages.
Lies directly below the thyroid cartilage at:
 C6- C7 level in adults and
 C3-C4 level in children
Composed of hyaline cartilage, but may become
partially ossified later in life (can be fractured in blunt
laryngeal trauma)
o Signet ring shape, widest posteriorl
o An infant’s airway is most narrow at the level of the
cricoid
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Laryngeal Framework
Anatomy
Halsey-VS Conf-5/7/09
Anatomy
Halsey-VS Conf-5/7/09
Muscles
Halsey-VS Conf-5/7/09
Membranes
Halsey-VS Conf-5/7/09
Valve
Halsey-VS Conf-5/7/09
Arytenoid Rotation
Halsey-VS Conf-5/7/09
Larynx
Halsey-VS Conf-5/7/09
Adductors
Cricothyroid-Adducts and stiffens the
vocal folds
Posterior Cricoarytenoid-the ONLY
abductor of the vocal folds
Intrinsic Muscles of the Larynx
• Cricothyroid:
o
adducts, stiffens VF
• Posterior cricoarytenoid:
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ONLY abductor; Also elevates, elongates, thins VF
• Lateral cricoarytenoid:
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adducts, depresses, elongates, thins VF
• Thyroarytenoid:
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medial portion forms the vocalis muscle; adducts,
shortens, depresses, and thickens VF
• Interarytenoid:
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adducts VF
Gaps
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Above the superior pharyngeal
constrictor:
auditory tube (AT)
levator palati (LP)
ascending palatine artery (APA)
Between the superior and middle
constrictors: stylopharyngeus muscle
(SP)
glossopharyngeal nerve (IX)
Between the middle and inferior
constrictors: internal laryngeal branch of
the superior laryngeal nerve (IL)
superior laryngeal artery from the
superior thyroid artery (SLA)
Below the inferior constrictor: inferior
laryngeal nerve ( ILN) (recurrent
laryngeal branch of the vagus)
inferior laryngeal artery (ILA) (inferior
thyroid)
Halsey-VS Conf-5/7/09
Nerves
• CN IX -- Glossopharyngeal
o
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contains both sensory and motor fibers
important for taste to posterior tongue, sensory and motor
functions of the pharynx
• CN X -- Vagus
contains both sensory and motor fibers
important for taste to oropharynx, and sensation and motor
function to larynx and laryngopharynx.
o important for airway protection
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• CN XII -- Hypoglossal
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contains motor fibers that primarily innervate the tongue
Halsey-VS Conf-5/7/09
Laryngeal Innervation
• Superior laryngeal nerve: leaves CN X at the
inferior vagal ganglion, travels deep and medial
to ICA
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At level of hyoid greater cornu, SLN branches into
internal and external
Internal SLN: through thyrohyoid membrane;
innervates supraglottic larynx and pharynx and
supraglottic minor salivary glands
External SLN: along inferior constrictor to the CT
muscle and inferior pharyngeal constrictor; also
contributes to pharyngeal plexus
Laryngeal Innervation
• Right recurrent laryngeal nerve: originates from CN X
near right subclavian artery
o Travels around subclavian a. and then runs in right
TE groove
• Left RLN: loops around aortic arch to travel in left TE
groove
• RLNs give off branches to the esophagus, trachea, and
inferior constrictor muscles
• RLN innervates all intrinsic laryngeal muscles except
CT; also subglottic sensation
Innervation