Podcast
Questions and Answers
Damage to the external branch of the superior laryngeal nerve would MOST directly affect which laryngeal muscle?
Damage to the external branch of the superior laryngeal nerve would MOST directly affect which laryngeal muscle?
- Transverse arytenoid muscle
- Thyroarytenoid muscle
- Cricothyroid muscle (correct)
- Posterior cricoarytenoid muscle
A surgeon is performing a thyroidectomy and inadvertently ligates a vessel that supplies the larynx above the vocal folds. Which vessel was MOST likely ligated?
A surgeon is performing a thyroidectomy and inadvertently ligates a vessel that supplies the larynx above the vocal folds. Which vessel was MOST likely ligated?
- Cricothyroid artery
- Inferior thyroid artery
- Inferior laryngeal artery
- Superior laryngeal artery (correct)
Which muscle is directly responsible for adducting the vocal folds?
Which muscle is directly responsible for adducting the vocal folds?
- Cricothyroid muscle
- Posterior cricoarytenoid muscle
- Lateral cricoarytenoid muscle (correct)
- Thyroarytenoid muscle
A patient presents with hoarseness after a surgical procedure. Further examination reveals impaired function of a muscle that originates from the posterior cricoid cartilage. Which muscle is MOST likely affected?
A patient presents with hoarseness after a surgical procedure. Further examination reveals impaired function of a muscle that originates from the posterior cricoid cartilage. Which muscle is MOST likely affected?
Which laryngeal muscle is NOT derived from the thyroarytenoid muscle?
Which laryngeal muscle is NOT derived from the thyroarytenoid muscle?
During an intubation procedure, a clinician inadvertently damages a nerve, resulting in the patient's inability to tense their vocal cords. Which nerve was MOST likely damaged during the procedure?
During an intubation procedure, a clinician inadvertently damages a nerve, resulting in the patient's inability to tense their vocal cords. Which nerve was MOST likely damaged during the procedure?
Which muscle is primarily responsible for lengthening and thinning the vocal folds to increase pitch?
Which muscle is primarily responsible for lengthening and thinning the vocal folds to increase pitch?
A patient presents with difficulty in swallowing and a change in voice. Imaging reveals a mass affecting the lateral surface of the cricoid cartilage. Which muscle's function would MOST likely be directly impaired by this mass?
A patient presents with difficulty in swallowing and a change in voice. Imaging reveals a mass affecting the lateral surface of the cricoid cartilage. Which muscle's function would MOST likely be directly impaired by this mass?
Damage to the inferior laryngeal artery would MOST directly compromise blood supply to which laryngeal structure?
Damage to the inferior laryngeal artery would MOST directly compromise blood supply to which laryngeal structure?
Following a surgical procedure, a patient presents with the inability to modulate the pitch of their voice. Which muscle is MOST likely affected by nerve damage?
Following a surgical procedure, a patient presents with the inability to modulate the pitch of their voice. Which muscle is MOST likely affected by nerve damage?
If the transverse arytenoid muscle is paralyzed, what specific vocal action would be MOST directly impaired?
If the transverse arytenoid muscle is paralyzed, what specific vocal action would be MOST directly impaired?
A patient undergoing thyroid surgery suffers damage to a nerve resulting in hoarseness and difficulty with phonation, but no difficulty breathing. Which nerve is MOST likely affected?
A patient undergoing thyroid surgery suffers damage to a nerve resulting in hoarseness and difficulty with phonation, but no difficulty breathing. Which nerve is MOST likely affected?
During an intubation procedure, a bolus of food is accidentally directed into the larynx. Which group of muscles would MOST directly prevent the entry of the bolus into the trachea by closing the laryngeal aditus?
During an intubation procedure, a bolus of food is accidentally directed into the larynx. Which group of muscles would MOST directly prevent the entry of the bolus into the trachea by closing the laryngeal aditus?
A surgeon is performing a delicate procedure near the larynx and needs to identify the nerve responsible for the abduction of the vocal folds to avoid iatrogenic injury. Which nerve and muscle pairing is MOST accurate?
A surgeon is performing a delicate procedure near the larynx and needs to identify the nerve responsible for the abduction of the vocal folds to avoid iatrogenic injury. Which nerve and muscle pairing is MOST accurate?
Damage to the cricothyroid joint would MOST directly affect which laryngeal function?
Damage to the cricothyroid joint would MOST directly affect which laryngeal function?
Which of the following BEST describes the primary function of the arytenoid cartilages?
Which of the following BEST describes the primary function of the arytenoid cartilages?
A patient complains of loss of sensation in the larynx superior to the vocal folds, but maintains motor control of the cricothyroid muscle. Which nerve is MOST likely damaged?
A patient complains of loss of sensation in the larynx superior to the vocal folds, but maintains motor control of the cricothyroid muscle. Which nerve is MOST likely damaged?
If the thyrohyoid membrane were severed, which structure would MOST directly lose its connection to the larynx?
If the thyrohyoid membrane were severed, which structure would MOST directly lose its connection to the larynx?
What is the MOST likely consequence of damage to the inferior pharyngeal constrictor muscle?
What is the MOST likely consequence of damage to the inferior pharyngeal constrictor muscle?
Which structural feature primarily prevents the epiglottis from collapsing during forceful swallowing?
Which structural feature primarily prevents the epiglottis from collapsing during forceful swallowing?
Which of the following BEST explains the functional relationship between the cricoid cartilage and the thyroid cartilage?
Which of the following BEST explains the functional relationship between the cricoid cartilage and the thyroid cartilage?
What is the MOST direct consequence of the absence or malformation of the cuneiform cartilages?
What is the MOST direct consequence of the absence or malformation of the cuneiform cartilages?
A surgeon inadvertently damages the sternothyroid muscle during a thyroidectomy. What is the MOST likely resulting symptom?
A surgeon inadvertently damages the sternothyroid muscle during a thyroidectomy. What is the MOST likely resulting symptom?
Compared to a female larynx, which characteristic is MOST likely to be observed in a male larynx due to hormonal influences?
Compared to a female larynx, which characteristic is MOST likely to be observed in a male larynx due to hormonal influences?
Damage to which nerve would directly impair the function of the intrinsic muscles responsible for controlling vocal cord tension and adduction during phonation?
Damage to which nerve would directly impair the function of the intrinsic muscles responsible for controlling vocal cord tension and adduction during phonation?
A surgeon needs to perform an emergency tracheotomy on an adult male. Considering the surface anatomy of the larynx, at which vertebral level should the incision ideally be made to minimize the risk of damaging adjacent structures?
A surgeon needs to perform an emergency tracheotomy on an adult male. Considering the surface anatomy of the larynx, at which vertebral level should the incision ideally be made to minimize the risk of damaging adjacent structures?
A patient presents with hoarseness and difficulty in modulating voice pitch following a surgical procedure. Which of the following structures is most likely to have been affected, resulting in these symptoms?
A patient presents with hoarseness and difficulty in modulating voice pitch following a surgical procedure. Which of the following structures is most likely to have been affected, resulting in these symptoms?
During an endoscopic examination of the larynx, a lesion is observed on the posterior aspect of the vocal folds, near the arytenoid cartilages. This lesion is most likely to directly affect which laryngeal function?
During an endoscopic examination of the larynx, a lesion is observed on the posterior aspect of the vocal folds, near the arytenoid cartilages. This lesion is most likely to directly affect which laryngeal function?
Damage to the lateral portion of the cricothyroid ligament would most directly affect which of the following functions?
Damage to the lateral portion of the cricothyroid ligament would most directly affect which of the following functions?
Following a neck trauma, a patient experiences difficulty swallowing and voice changes. Imaging reveals damage to the superior laryngeal nerve. Which specific sensory deficit would you expect to observe during examination?
Following a neck trauma, a patient experiences difficulty swallowing and voice changes. Imaging reveals damage to the superior laryngeal nerve. Which specific sensory deficit would you expect to observe during examination?
A patient is diagnosed with a tumor affecting the laryngopharynx. Considering the anatomical relationships, which of the following adjacent structures is at the highest risk of being directly invaded by the tumor's spread?
A patient is diagnosed with a tumor affecting the laryngopharynx. Considering the anatomical relationships, which of the following adjacent structures is at the highest risk of being directly invaded by the tumor's spread?
A surgeon performing a laryngectomy accidentally severs the quadrangular membrane. Which secondary structure is most likely to be directly affected by this error?
A surgeon performing a laryngectomy accidentally severs the quadrangular membrane. Which secondary structure is most likely to be directly affected by this error?
A lesion affecting the aryepiglottic fold is most likely to directly impact which of the following processes?
A lesion affecting the aryepiglottic fold is most likely to directly impact which of the following processes?
A medical student is palpating the anterior neck region to identify laryngeal structures. Which of the following landmarks would be most useful in locating the cricothyroid ligament?
A medical student is palpating the anterior neck region to identify laryngeal structures. Which of the following landmarks would be most useful in locating the cricothyroid ligament?
If a foreign object becomes lodged in the ventricle of the larynx, which of the following structures would be located immediately superior to the obstruction?
If a foreign object becomes lodged in the ventricle of the larynx, which of the following structures would be located immediately superior to the obstruction?
Which of the following conditions would most directly result from the weakening of the conus elasticus?
Which of the following conditions would most directly result from the weakening of the conus elasticus?
A patient presents with hoarseness due to swelling in the rima glottidis. Which anatomical structure is most directly affected by this swelling?
A patient presents with hoarseness due to swelling in the rima glottidis. Which anatomical structure is most directly affected by this swelling?
During an advanced surgical procedure, a surgeon needs to access the infraglottic space. Through which structure would the surgeon gain the most direct access?
During an advanced surgical procedure, a surgeon needs to access the infraglottic space. Through which structure would the surgeon gain the most direct access?
If the mucosa over the vestibular ligament is damaged, which of the following functions would be least directly affected?
If the mucosa over the vestibular ligament is damaged, which of the following functions would be least directly affected?
A patient's voice is strained due to increased tension in the vocal ligaments. Which of the following structures is most directly responsible for modulating this tension?
A patient's voice is strained due to increased tension in the vocal ligaments. Which of the following structures is most directly responsible for modulating this tension?
Damage to which of the following structures would most directly impair the definition of the laryngeal aditus?
Damage to which of the following structures would most directly impair the definition of the laryngeal aditus?
Flashcards
Larynx Function
Larynx Function
An anatomical valve directing air into the respiratory system and food/liquids into the digestive system; also provides phonation.
Larynx Position
Larynx Position
The larynx is positioned in the anterior neck, anterior to the laryngopharynx and related in position to the thyroid gland.
Larynx Vertebral Level
Larynx Vertebral Level
C3-C6 vertebrae.
Palpable Larynx Structures
Palpable Larynx Structures
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Laryngeal Cartilages
Laryngeal Cartilages
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Larynx Composition
Larynx Composition
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Larynx Superior Opening
Larynx Superior Opening
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Larynx
Larynx
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Thyroid Cartilage
Thyroid Cartilage
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Superior Horns (Thyroid)
Superior Horns (Thyroid)
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Cricoid Cartilage
Cricoid Cartilage
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Cricothyroid Joint
Cricothyroid Joint
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Cricothyroid Ligament
Cricothyroid Ligament
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Arytenoid Cartilages
Arytenoid Cartilages
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Corniculate & Cuneiform Cartilages
Corniculate & Cuneiform Cartilages
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Epiglottic Cartilage
Epiglottic Cartilage
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External Laryngeal Nerve Function
External Laryngeal Nerve Function
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Internal Laryngeal Nerve Function
Internal Laryngeal Nerve Function
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Recurrent Laryngeal Nerve Function
Recurrent Laryngeal Nerve Function
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Cricothyroid Muscle Action
Cricothyroid Muscle Action
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Posterior Cricoarytenoid (PCA) Muscle Action
Posterior Cricoarytenoid (PCA) Muscle Action
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Median Cricothyroid Ligament
Median Cricothyroid Ligament
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Lateral Cricothyroid Ligament
Lateral Cricothyroid Ligament
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Vocal Ligament
Vocal Ligament
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Conus Elasticus
Conus Elasticus
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Quadrangular Membrane
Quadrangular Membrane
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Aryepiglottic Fold
Aryepiglottic Fold
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Vestibular Ligament
Vestibular Ligament
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Laryngeal Vestibule
Laryngeal Vestibule
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Laryngeal Ventricle
Laryngeal Ventricle
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Cricothyroid Muscle
Cricothyroid Muscle
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Thyroarytenoid Muscle
Thyroarytenoid Muscle
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Posterior Cricoarytenoid Muscle
Posterior Cricoarytenoid Muscle
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Lateral Cricoarytenoid Muscle
Lateral Cricoarytenoid Muscle
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Transverse Arytenoid Muscle
Transverse Arytenoid Muscle
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Oblique Arytenoid Muscle
Oblique Arytenoid Muscle
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Aryepiglottic Muscle
Aryepiglottic Muscle
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Thyroepiglottic Muscle
Thyroepiglottic Muscle
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Vocalis Muscle
Vocalis Muscle
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Superior Laryngeal Artery
Superior Laryngeal Artery
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Study Notes
Anatomy of the Larynx
- The larynx is an anatomical valve which allows air to the respiratory system while directing food and liquids to the digestive system.
- It also provides the phonating mechanism for voice production.
- The larynx relates in position to the thyroid gland and is part of the laryngopharynx.
Surface Anatomy
- The larynx spans the position of C3-C6 vertebrae.
- It is approximately 5 cm long in adult males, and slightly shorter in females and children.
- The following structures can be palpated: laryngeal prominence, cricoid arch, cricothyroid ligament & thyroid gland.
Structural Anatomy of Laryngeal Cartilages
- The cartilaginous is made up of 9 cartilages (3 paired, 3 unpaired)
- It also contains a fibro-elastic membrane with intrinsic muscles (musculoligamentous)
- The cartilages are covered with mucosa, the same as in the laryngopharynx.
- Superiorly they open into the pharynx, while inferiorly, they are continuous with the trachea.
- They're attached to the hyoid bone above and the trachea below
- Structure is very mobile, elevates and moves forward during swallowing, while also moving considerably during phonation.
Thyroid Cartilage
- Single cartilage, made up of two thin plates known called thyroid lamina.
- These fuse anteriorly to form the laryngeal prominence, which has a sharper angle in males.
- Superior and inferior horns are located posteriorly on each lamina.
- Inferior pharyngeal constrictor, thyrohyoid and sternothyroid mm. are attached to each laminae.
- The superior horn of each lamina attaches to the hyoid bone by the thyrohyoid membrane.
Cricoid Cartilage
- Location of the singe cartilage is inferior to that of the thyroid cartilage, and at the CV6 level.
- Shape is similar to a signet ring, with the thick part pointing directly posteriorly.
- Connection to the inferior horn of the thyroid lamina occurs via special facets (cricothyroid joint) to allow the tilting of the thyroid cartilage upon the cricoid cartilage.
- The cricothyroid ligament provides the fibroelastic connection between thyroid and cricoid cartilages.
Arytenoid Cartilages
- Paired cartilages that sits atop the posterior cricoid cartilage.
- Shaped like 3-sided pyramids, base part attaches to intrinsic laryngeal muscles and vocal ligaments.
- The apex attaches to a fold which helps close the larynx during swallowing.
Corniculate & Cuneiform Cartilages
- These are paired cartilages, located on top of the arytenoids (corniculate) or in a laryngeal fold (cuneiform).
- Stabilize the structural integrity of the laryngeal folds.
Epiglottic Cartilage
- Singular cartilage, leaf-shaped.
- Inferior part attaches to the thyroid cartilage via the thyroepiglottic ligament.
- Connection to the hyoid bone anteriorly is via the hyoepiglottic ligament.
- Helps close up for when swallowing
Cricothyroid Ligament
- Extends superiorly from the lateral and anterior parts of the cricoid cartilage.
- The anterior part is called the median cricothyroid ligament.
- The lateral part is called the lateral cricothyroid ligament.
- The top edge attaches to the vocal ligament.
Vocal Ligament
- Forms the true vocal cord.
- Elastic and extends from the laryngeal prominence to the vocal processes of the arytenoid cartilages.
- The cricothyroid ligament along with the vocal ligament makes up the conus elasticus.
- Mucosa over the vocal ligament forms the vocal folds.
Quadrangular Membrane
- Extends from the lateral margin of the epiglottis to the ipsilateral arytenoid cartilage.
- Encloses both cuneiform and corniculate cartilages.
- Its superior edge forms the aryepiglottic fold, which is part of the inlet to the larynx.
- Its inferior edge attaches to the vestibular ligament
Vestibular Ligament
- Forms the false vocal cord.
- Extends from the thyroid to arytenoid cartilages, it sits parallel but superior to the vocal ligaments
- Attaches to the inferior free edge of the quadrangular membrane.
- Mucosa over the vestibular ligament forms the vestibular folds.
Compartments of the Larynx
- Vestibule: Cavity superior to vestibular folds (false vocal cords) up to the aryepiglottic folds.
- Ventricle: Smallest cavity that extends laterally between the vestibular folds and superior to vocal folds.
- Infraglottic: area that extends from the vocal folds to the inferior border of the cricoid cartilage.
Additional Terms
- Laryngeal aditus: Opening into the vestibule bordered by the aryepiglottic fold.
- Rima glottidis: Space between the vocal folds
Laryngeal Muscles
- Cricothyroid M: originates from anterolateral cricoid cartilage and inserts on the inferior horn and margin of thyroid cartilage.
- Thyroarytenoid M: originates from the thyroid angle and inserts into the arytenoid cartilage.
- Posterior cricoarytenoid M: originates from posterior cricoid cartilage and inserts on the muscular processes of the arytenoid cartilages.
- Lateral cricoarytenoid M: originates from the lateral surface of cricoid cartilage and inserts on the muscular processes of the arytenoid cartilages.
- Transverse arytenoid M: spans the posterior surfaces of the arytenoid cartilages from one lateral border to the other.
- Oblique arytenoid M: originates from the inferior posterior surface of the arytenoid and inserts into the apex of the contralateral arytenoid.
- Aryepiglottic M: continuation of the oblique arytenoid, as a muscular slip to insert into the contralateral aryepiglottic fold.
- Thyroepiglottic M: originates from the thyroid cartilage and inserts on the epiglottic cartilage, derived from the thyroarytenoid muscle.
- Vocalis M: originates from vocal process of arytenoid and inserts into the vocal ligament and thyroid angle; also is derived from the thyroarytenoid muscle.
Blood Supply of Larynx
- Superior laryngeal a. (branch of superior thyroid a.) supplies larynx at or above the vocal folds.
- Inferior laryngeal a. (branch of inferior thyroid a.) supplies larynx at or below the level of the vocal folds.
Innervation of the Larynx
- Superior laryngeal nerve. (CN X) divides into the external laryngeal nerve and the internal laryngeal nerve.
- External laryngeal n. provides motor innervation to the cricothyroid m.
- Infernal laryngeal n. pierces thyrohyoid and provides sensory innervation to the larynx superior to the vocal folds
- Recurrent laryngeal nerve provides motor innervation to all intrinsic laryngeal muscles except cricothyroid.
- Larynx mucosa that is inferior to the vocal folds is innervated by the sensory fibers within the recurrent laryngeal nerve.
- Mucosa of the vocal folds are innervated by an overlap of fibers from both internal laryngeal and recurrent laryngeal nerves.
Phonation
- Contraction of the cricothyroid muscle causes the thyroid cartilage to tilt anteriorly upon the cricoid.
- This elongates and tightens the vocal ligaments to raise voice pitch.
- Contraction of the thyroarytenoid muscle shortens the distance between the laryngeal prominence and vocal process of the arytenoids, thus causing the vocal ligaments to slacken which lowers voice pitch.
- Vocalis m. is part of the thyroarytenoid m. and makes precision adjustments to the tension of the vocal ligaments.
Respiration
- Lateral cricoarytenoid adducts the vocal ligaments by causing internal (medial) rotation of the arytenoid vocal processes, closes the rima glottidis.
- Posterior cricoarytenoid abducts the vocal ligaments by causing external (lateral) rotation of the arytenoid vocal processes which opens the rima glottidis.
Valve Mechanism
- Arytenoid, transverse & oblique, bring the arytenoid cartilages closer to one another to help close the laryngeal aditus.
- Aryepiglottic cinches the aryepiglottic folds together to close the laryngeal aditus.
- Thyroepiglottic approximates the epiglottis to the aryepiglottic folds, which also closes the laryngeal aditus.
Viewing the Larynx
- The larynx may be observed with a laryngoscopic mirror or an endoscopic instrument called a laryngoscope.
- Both vestibular (pink) and vocal or (white), folds can be visualized as well as the location of the arytenoid cartilages, aryepiglottic folds, epiglottis, and the trachea.
- Visualization of the vocal folds and the rima glottidis during normal breathing and phonation is useful to determine the extent of damage to the larynx that may occur as a result of trauma, tumor growth or damage to the recurrent laryngeal nerves during thyroidectomy.
Laryngeal Obstruction
- Laryngeal spasm triggered by "food-down-the-wrong-pipe" is different than a laryngeal obstruction which blocks airflow to the trachea (choking).
- The former elicits coughing due to touch sensitivity of the laryngeal aditus, but the person can breathe and reply "I'm okay" between coughs.
- Choking occurs when an object becomes lodged in the rima glottidis, completely blocking air to the trachea. Subsequently results in unconsciousness.
- At this point, a Heimlich maneuver must be performed. Choking occurs more commonly at restaurants where alcohol, which reduces the sensitivity of the laryngeal aditus, is consumed.
Cricothyrotomy vs. Tracheotomy
- An emergency cricothyrotomy is performed through the median cricothyroid ligament with a tube inserted to provide an air passage to the lungs.
- This procedure is superior to the thyroid gland isthmus and inferior to the vocal ligaments.
- However, the proximity of the tube insertion places the vocal ligaments at risk of damage and is a short-term solution to establish an airway.
- The procedure for a tracheotomy (slit incision in the trachea) or tracheostomy (round or square hole) is no simple task given the structures that lie deep to the incision.
- The most common approach involves a transverse at the level of the 2nd-3rd tracheal rings.
CN X Injury
- Recurrent laryngeal nerve, can be accidently severed during surgery of the neck (e.g. thyroidectomy).
- Bilateral lesions result in paralysis of laryngeal intrinsic muscles with the overall result being the narrowing of the rima glottidis and suffocation.
- CN X can become damaged including CNS diseases (e.g. bulbar palsy) that affect swallowing, phonation, and respiration.
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