Airway Anatomy Flashcards
What is the function of the intrinsic muscles?
Phonation and vocal cord movement
What is the function of the extrinsic muscles?
support the larynx inside the neck and assist with swallowing
The true vocal cords are innervated by which nerve?
None. They are ligaments, not muscles
The true vocal cords attach to the _____ anteriorly and the _____ posteriorly
Thyroid
Arytenoids
Identify the pink muscle. List its action and innervation.
Cricothyroid
Elongates (tenses) vocal cords
External SLN
Identify the green muscle.
List its action and innervation.
Thyroarytenoid
Shortens (relaxes) vocal cords
ADDucts the vocal folds (closes the glottis)
RLN
Identify the green muscle.
List its action and innervation.
Thyroarytenoid
Shortens (relaxes) vocal cords
ADDucts the vocal folds (closes the glottis)
RLN
Identify the purple muscle.
List its action and innervation.
Vocalis
Shortens (relaxes) vocal cords
RLN
Identify the blue muscle.
List its action and innervation.
Lateral Cricoarytenoid
ADDucts vocal folds (closes glottis)
RLN
Identify the orange muscle.
List its action and innervation.
Posterior cricoarytenoid
ABDucts the vocal folds (opens the glottis)
Identify the structure in the green box.
Posterior cricoarytenoid
Identify the structure in the purple box.
Cuneiform Cartilage
Identify the structure in the blue box
Corniculate Cartilage
Identify the structures in pink.
List their function and innervation.
Interarytenoids (transverse and oblique)
Closes posterior commissure of the glottis
RLN
Identify the structure indicated by yellow arrows.
List its function and innervation.
Aryepiglottic
Closes the laryngeal vestibule
RLN
Which muscle(s) relax/shorten the vocal ligaments?
Vocalis
Thyroarytenoid (“They Relax”)
Which muscle(s) tense/elongate the vocal ligaments?
Cricothyroid
“Cords Tense”
Which muscle(s) ADDuct the vocal folds?
What is the outcome of this?
Thyroarytenoid
Lateral Cricothyroid
Narrowing the glottis
Which muscles function as sphincters?
Aryepiglottic (Closes laryngeal vestibule)
Interarytenoids (Closes posterior commissure of glottis)
Which muscles elevate the larynx?
Which muscles depress the larynx?
Which muscle has both intrinsic and extrinsic actions?
Cricothyroid Mm
Which muscles ABDuct the vocal cords?
Posterior Crico Arytenoids
“Please Come Apart”
Which muscles ADDucts the vocal cords?
Lateral CricoArytenoid
(Let’s Close the Airway)
The internal branch of the SLN is a _______ nerve.
The external branch of the SLN is a ______ nerve.
Sensory
Motor
What does the internal branch of the SLN innervate?
provides sensory to the posterior side of the epiglottis to the top side of the vocal cords
NO MOTOR FUNCTION
What does the external branch of the SLN innervate?
Provides motor innervation to the cricothyroid mm.
NO SENSORY FUNCTION
The nerves of the airway arise from which three cranial nerves?
Trigeminal (V)
Glossopharyngeal (IX)
Vagus (XII)
Identify the nerves marked.
These are the branches of the trigeminal nerve (yellow):
Purple: ophthalmic
Orange: Maxillary
Blue: Mandibular
What does the lingual nerve innervate?
Trace its origin.
Sensory: Anterior ⅔ of the tongue
Trigeminal → Mandibular → Lingual
What does the sphenopalatine nerve innervate?
Trace its origin.
SENSORY; Turbinates and posterior ⅔ of nasal septum
Trigeminal → Maxillary → Sphenopalatine
The trigeminal nerve provides _____ innervation to the face
SENSORY
What does the anterior ethmoidal nerve innervate? Trace its origin.
SENSORY: Nares and anterior ⅓ of nasal septum
Trigeminal → Ophthalmic → Anterior Ethmoidal
The gag reflex is completed by two nerves:
Afferent limb:
Efferent limb:
Afferent: Glossopharyngeal (responds to soft palate stimulation)
Efferent: Vagus (causes pharyngeal constriction)
Which nerves provides sensory innervation to the posterior ⅓ of the tongue?
Glossopharyngeal
Which nerve provides sensory innervation to the oropharynx and valecula?
Glossopharnygeal
The Vagus Nerve branches into the:
Superior Laryngeal
Recurrent Laryngeal
What is the function of the internal branch of the SLN?
SENSORY ONLY
Posterior side of the epiglottis to the level of the vocal cords
What is the function of the external branch of the SLN?
MOTOR
Cricothyroid Muscles
What would happen if the trunk of the SLN or its external branch are injured?
Hoarseness, but no respiratory distress
Which nerve provides sensory innervation below the level of the folds?
The recurrent laryngeal
Both recurrent laryngeal nerves branch off of the _______.
The R RLN loops under the ______
The L RLN loops under the ______
Vagus
Subclavian Artery
Aortic Arch
Which RLN is more susceptible to injury?
The Left, because it is in the thorax
What happens when unilateral RLN damage occurs?
Ipsilateral (same side) paralysis of ABDuctor motion cause unopposed ADDuctor motion, and that side will NOT OPEN
In bilateral recurrent laryngeal nerve injury, why do the vocal cords snap shut?
The ADDucting motion of the posterior cricoarytenoids is unopposed, and causes the cords to snap shut
Tongue movement is provided by which nerve?
Hypoglossal (CN 12)
What tends to cause L RLN unilateral injury?
Stuff in the thorax:
L Atrial Enlargement (from mitral stenosis)
Aortic Arch Aneurysm
PDA ligation
Thoracic Tumor
Which muscle serves as the “tuning fork” of the larynx?
Cricothyroid
Which RLN is injured in this patient?
The Left RLN
