Airway Flashcards
What is the only bone in the larynx?
Hyoid bone
What are the single cartilages in the larynx?
thyroid
cricoid
epiglottic
What are the paired cartilages in the larynx?
corniculate
arytenoid
cuneiform
What is the valleculae?
Space on the other side of the epiglottis where you can put the MAC blade
What is the epiglottis?
fibrous cartilage with mucous membrane covering that reflects up to the paryngeal surface of the tongue and makes the glossoepiglottic fold, its at base of tongue and separates hypopharynx from the larynx and hangs over the laryngeal opening
prevents against aspiration by covering glottis during swallowing
Is the epiglottis a vascular area?
Yes, very vascular area and can be traumatized and swell incredibly
What are the components of the upper airway?
Nose Mouth Pharynx Hypopharynx Larynx
What are the components of the lower airway?
Trachea Bronchi Bronchioles Terminal Bronchioles Respiratory Bronchioles Alveoli
Where is gas warmed and humidified?
Nose
What is the primary pathway for normal breathing?
Nose, unless there is an obstruction, polyps, or upper respiratory infection
Resistance is almost 2 times that of mouth breathing
Mouth breathing is utilized with high flow rates such as that seen with exercise
What are the 3 compartments of the pharynx?
Nasopharynx
Oropharynx
Hypopharynx
Where does the pharynx extend?
extends from posterior aspect of nose to the level of the cricoid cartilage
Where is the nasopharynx?
Anterior to C1, bound superiorly by base of skull and inferiorly by soft palate
What structures are in the nasopharynx?
nasal septum, turbinates, and adenoids
Where is the oropharynx?
Lies at C2-C3
Bound superiorly by soft palate and inferiorly by epiglottis
What is a major source of obstruction in the oropharynx?
Tongue due to decreased genioglossus muscle tone with anesthesia
Where is the hypopharynx?
Bound by superior border of epiglottis and inferior border of the cricoid cartilage at C5-C6
Lies posterior to the larynx and leads to the esophagus
What lies at the lower edge of the hypopharynx and acts as a barrier to regurgitation in the conscious patient?
Upper esophageal sphincter, closes when swallowing and opens when breathing
What is Waldeyer’s Tonsillar Ring?
lymphoid tissue ring in the pharynx that is at high risk for bleeding, especially with nasal intubation
What makes up the Waldeyer’s Tonsillar Ring?
Pharyngeal tonsils (adenoids) in nasopharynx, palatine tonsils (oropharynx), lingual tonsils (located at base of tongue)
Where is the larynx?
Lies at C3-C6 in adults
Lies at C2-C4 in infants and descends to C4-C5 by age of 5
What is the organ of phonation and serves as a valve to protect the lower airways?
larynx
Where does the larynx extend?
Extends from epiglottis to lower level of cricoid cartilage and sits at the junction of the airway and the esophagus
Attached anteriorly by the epiglottis, posteriorly by the mucous membrane which extends between the arytenoid cartilage and laterally by the aryepiglottic folds (false vocal cords)
What is the most commonly seen paired cartilages in laryngoscopy?
arytenoids
What are narrow bands of fibrous tissue one each side of the larynx that are found first inside the laryngeal cavity opening?
vestibular folds aka false vocal cords
What are pale, white, ligamentous structures that attach to the thyroid anteriorly and the arytenoids posteriorly?
true vocal cords
What is the triangular fissure between the vocal cords?
glottic opening
Where is the narrowest portion of an adult airway and what is its average width?
Glottic opening, width of 6-9 mm (can be stretched to 12 mm)
What is the largest cartilage of the larynx?
Thyroid cartilage
What is the only complete ring in the upper airway and where is it?
cricoid cartilage, sits at C6, narrowest part of the airway in a child
Where is the site for Selleck’s Maneuver?
cricoid cartilage
How much pressure is needed for Selleck’s Maneuver?
6.6-8.8 lbs
What connects the thyroid cartilage with the hyoid bone?
thyrohoid
Is the cricothyroid membrane vascular or avascular?
avascular
Where is the site for translaryngeal injection and emergency airway?
cricothyroid membrane
Where does the trachea begin and end?
Begins at C6 at the inferior border of the cricoid cartilage and extends to the carina
About how long is the trachea?
10-15 cm in length
Where do the left and right mainstem bronchus bifurcate?
level of T5
What angle does the right bronchus bifurcate?
25-30 degree angle
Shallow and favors intubation
What angle does the left bronchus bifurcate?
45 degree angle
How is the pediatric airway different than the adult airway?
larynx positioned higher in the neck
tongue larger relative to mouth size
epiglottis larger, stiffer, angled more posteriorly
head and occiput larger relative to body size
short neck
narrow nares
cricoid ring is narrowest region
What is the purpose of muscles in the airway?
Adduct, abduct, regulate tension, or physically move the larynx
What is the role of intrinsic muscles?
responsible for opening, closing, and controlling tension of the vocal cords
What is the role of extrinsic muscles?
connect the larynx with the hyoid bone and other structures and serve to move the larynx as a whole (elevating and depressing) during phonation, swallowing, and breathing
What does the posterior cricoarytenoid muscle do?
abducts (opens) the vocal cords and opens the glottis
intrinsic muscle
What does the lateral cricoarytenoid muscle do?
adducts (closes) the vocal cords
intrinsic muscle
What do the arytenoid muscles do?
adducts the vocal cords
intrinsic muscle
What does the cricothyroid muscle do?
produces cord tension, closure, and elongates the vocal cords
can result in total and profound glottic closure, called laryngospasm
intrinsic muscle
What does the thyroarytenoid muscle do?
shortens and relaxes the vocal cords
intrinsic muscle
What does the sternohyoid muscle do?
Draws hyoid bone inferiorly
Extrinsic muscle
What does the sternothyroid muscle do?
Draw thyroid cartilage caudad (toward feet)
Extrinsic muscle
What does the thyrohyoid muscle do?
Draws hyoid bone inferiorly
Extrinsic muscle
What does the omohyoid muscle do?
Draws hyoid bone caudad
Extrinsic muscle
What does the stylohyoid muscle do?
Elevates larynx
Extrinsic muscle
What does the mylohyoid muscle do?
Elevates larynx
Extrinsic muscle
Which cranial nerves innervate the upper airway?
trigeminal - nasopharynx
glossopharyngeal - oropharynx
vagus - hypopharynx
What nerve innervates the anterior septum and lateral walls of the nose?
ophthalmic division of trigeminal nerve or more specifically the anterior ethmoidal nerve
What nerve innervates the posterior septum of nerve?
maxillary division of trigeminal nerve
more specifically nasopalatine nerves and sphenopalatine ganglion
What does sympathetic stimulation do to the nose?
vasoconstriction and shrinkage of nasal tissue
What does parasympathetic stimulation do to the nose?
engorgement of blood vessels and increases likelihood of bleeding with airway manipulation (seen with general anesthesia)
nasal airway could cause significant nose bleed
What is the sensory innervation of tonsils, roof of pharynx, and underside of soft palate?
glossopharyngeal nerve
What nerve innervates anterior 2/3 of tongue?
lingual nerve (mandicular dicision of trigeminal nerve)
What nerve innervates posterior 1/3 of tongue?
glossopharyngeal nerve
What areas does the facial nerve (CNVII) innervate?
supplies muscles of facial expression
taste to anterior 2/3 of tongue
small amount of afferent conduction to oropharynx
motor control of stylohyoid laryngeal muscle
salivary glands (parasympathetic stimulation increases saliva production)
What does the hypoglossal nerve (CNXII) do?
- provides motor innervation to most muscles of the tongue
- damage to the hypoglossal nerve can relax the tongue, causing it to fall back and cause airway obstruction
What area does the vagus nerve (CNX) innervate?
airway below the epiglottis
What branch of vagus nerve provides sensation to larynx from epiglottis to vocal cords (sensation above vocal cords)?
internal superior laryngeal nerve (SLN)
internal = SENSORY
What does the external branch of the SLN do?
provides motor innervation to cricothyroid muscle
External = MOTOR
What nerve provides sensation to larynx below the vocal cords and innervates all muscles of the larynx except for the cricothyroid muscle?
recurrent laryngeal nerve (RLN)
What happens with a vagal nerve injury?
affects both SLN and RLN
bilateral vagal denervations produces flaccid, midpositioned cords, resulting in aphonia
What occurs with unilateral superior laryngeal nerve injury?
minimal effects
What occurs with bilateral superior laryngeal nerve injury?
hoarseness, vocal tiring
What occurs with unilateral recurrent laryngeal nerve damage?
Hoarseness
What happens with bilateral recurrent laryngeal nerve damage?
Acute: stridor, respiratory distress from unopposed tension of the cricothyroid muscle
Chronic: aphonia
What area does the superior laryngeal artery (SLA) provide blood to?
- supraglottic laryngeal structures
- carotid to the superior thyroid artery to SLA
