Respiratory Anatomy Flashcards
Name the 5 INTRINSIC muscles of the airway
Cricothyroid
Thyroarytenoid
Lateral cricoarytnoid
Posterior cricoarytnoid
Vocalis
What does the Cricothyroid do
Elongates (tenses cords)
“Cords Tense”
What does the thyroarytenoid muscle do?
Shortens (relaxes cords) ~ muscles shorten
“They relax”
This leads to ADDuction of cords
What does the posterior cricoarytnoid muscles do
ABDucts vocal cords
“Please come apart”
What do the lateral cricoarytenoid muscles do?
ADDuct the vocal cords
“Let’s Close Airway”
What is cranial nerve 5
Trigeminal Nerve
How many branches are there to the trigeminal nerve
3
Ophthalmic nerve (V1)
Maxillary Nerve (V2)
Mandibular (V3)
What does the opthalamic nerve innervate?
First 1/3 of the nasal septum
What does the maxillary nerve (V2) innervate?
Turbinates, posterior 2/3 of the nasal septum
What does the mandibular nerve innervate?
Anterior 2/3 of the tongue
What does the glossopharyngeal nerve innervate?
Posterior 1/3 of the tongue, oropharynx, vallecula, and anterior side of epiglottis
What cranial nerve is the glossopharyngeal nerve
9
What is cranial nerve 10?
The Vagus nerve
What two nerves originate from the Vagus?
Superior laryngeal
Recurrent laryngeal
What does the superior laryngeal nerve divide into?
Internal branch (pierces the thyrohyoid membrane
External branch
What does the internal branch of the superior laryngeal nerve innervate?
Sensory.
Posterior side of the epiglottis to the level of the vocal cords
What does the external branch of the superior laryngeal nerve innervate?
Cricothyroid muscle
Acute injury to the superior laryngeal nerve causes what?
Hoarseness
What does the recurrent laryngeal nerve innervate?
Below the level of the vocal cords to the trachea
What happens with injury to the recurrent laryngeal nerve?
Unilateral: hoarseness
Bilateral: strider/resp distress
Where do the recurrent laryngeal branches loop?
Right: under the right subclavian artery
Left: under the aorta (this is more susceptible to injury)
What are the three cranial nerves that innervate the upper airway?
Trigeminal
Glossopharyngeal
Vagus
What 3 nerves must you block for an awake fiberoptic?
Glossopharyngeal
Superior laryngeal
Recurrent laryngeal
Where is your site of injection for a glossopharyngeal block?
Base of the palatoglossal arch (tonsillar pillar)
Must repeat on the other side!
Where is your site of injection for a superior laryngeal block?
Greater Cornu of the hyoid bone
Must repeat on the other side!
Where is your site of injection for a recurrent laryngeal block?
Puncture the Cricothyroid membrane and advance in a CAUDAL direction
Coughing is good!
Where does the ADULT airway lie?
C4-C6
What are 3 functions of the larynx?
Airway protection, respiration, and phonation
How many cartilages does the larynx have?
9 (3 PAIRED cartilages)
3 unpaired cartilages
What are the 9 cartilages of the airway?
Paired: arytenoids, cuneiform, corniculate
Unpaired: thyroid, epiglottis, cricoid
What is the narrowest region of the airway in adults?
The glottis opening
What is the narrowest region of the airway in kids?
It’s tricky!
Narrowest fixed region: cricoid ring
Narrowest dynamic region: vocal cords
What is the laryngospasm reflex pathway?
Afferent limb: internal branch of the SLN
Efferent limb: external branch of the SLN or recurrent laryngeal nerve branches (thyroarytenoid and lateral cricoarytenoid branches)
What are some pre-anesthetic risk factors to laryngospasm
Resp infections
Second-hand smoke
Reactive airway disease
Age < 1 year
What are some intra-anesthetic risk factors for laryngospasm?
Light anesthesia
Saliva/blood
Hyperventilation/hypocapnia
Surgical procedures of the airway (tonsils, palate, nasal/sinus, laryngoscopy)
How do you break a laryngospasm
- 100% FiO2
- Remove stimulation
- Deepens anesthetic (prop)
- CPAP 15-20 (with larsens)
- Administer Sux (IM 4mg/kg; IV 1mg/kg)
What is Larsen’s maneuver?
Firm pressure on laryngospasm notch. Pushes mandible anteriorly and causes patient to sigh
What is a valsalva’s maneuver?
Exhalation against a closed glottis (coughing, bucking, bearing down)
Increases pressure to in thorax, abd, and brian
What is Muller’s maneuver?
Inhalation against a closed glottis (patient bites ETT)
Negative pressure pulmonary edema due to subatmospheric pressure in thorax
What causes obstruction at the level of the tongue?
Genioglossus muscle relaxation
What causes obstruction at the level of the soft palate?
Tensor palatine muscle relaxation
Where does the trachea begin and end?
Begins C6
Ends T5 (carina)
Where is the carina and what does it correspond with?
T5 and it corresponds with the Angle of Louis
What allows movement between cells?
Pores of Kohn
What do type 1 pneumocytes do?
Gas exchange
Cover 80% of alveolar surface
What do type 2 pneumocytes do?
Produce surfactant
What does type 3 pneumocytes do?
They are macrophages
They fight lung infection and produce inflammatory responses
Are neutrophils present in the airway?
They are present in patients who are smokers or with acute lung injury.
What is the distance from the incisors to the larynx?
13 cms
What is the distance from the larynx to the carina?
13 cms
What is the tot distance from the incisors to the carina
26 cm
Think the entire length of an ETT
What increases as the airway progresses?
Number of airways
Total cross-sectional area
What decreases as the airway progresses (I.e goes from the trachea to the bronchioles)
Airway velocity
Airway cartilage
Goblets cells
Ciliated cells
