15 Pharynx and Larynx

Question 1

A patient had a tumor at the jugular foramen. What would be a neurological deficit?

Answer 1

The jugular foramen is the route of exit for CN IX, CN X and CN XI as well as the IJV. The glossopharygeal nerve provides sensory input for the gag reflex whereas the vagus nerve provides the motor output. Nerve compression within the foramen would lead to a loss of both systems and thus no gag reflex.

Question 2

An endotracheal tube is passed through an opening between the vocal folds. What is the name of this opening?

Answer 2

The rima glottidis is the opening between the vocal folds and the arytenoid cartilages on the right and left sides.

Question 3

A patient has difficulty coughing and swallowing. An MRI scan shows a tumor affecting which cranial nerve?

Answer 3

The vagus nerve is responsible for sensation in the mucosa of the larynx down to the level of the vocal folds and also motor innervation of the muscles that initiate a cough reflex and swallowing.

The glossopharyngeal nerve provides sensory innervation to the pharynx (gag reflex) and motor innervation to the stylopharyngeus muscle.

Question 4

A patient coughs during inspection of the external auditory meatus. The cough results from the irritation of which nerve that innervates an area of the external auditory meatus?

Answer 4

The vagus nerve innervates a part of the external auditory meatus and, when stimulated, can trigger a cough reflex.

Question 5

A patient underwent thyroidectomy and had hoarseness of voice post-operation. What nerve was injured?

Answer 5

The recurrent laryngeal nerve supplies most of the motor innervation to the larynx and sensation below the true vocal folds. The tyroid gland and the recurrent laryngeal nerve are in close proximity.

Question 6

Name the 2 branches of the superior laryngeal nerve

Answer 6

• internal laryngeal nerve
  
  • innervates the mucous membrane of the larynx above the vocal folds
• external laryngeal nerve
  
  • innervates the cricothyroid muscle which tenses the vocal folds

Question 7

Before laryngela intubation the rima glottidis is opened by which pair of muscles?

Answer 7

The posterior cricoarytenoid muscles lie on the superoposterior aspect of the lamina of the cricoid cartilage. When these muscles contract, they cause lateral roation (abudction) of the vocal processes of the arytenoid cartilages, thereby opening the space between the vocal folds, the rima glottidis.

The lateral cricoarytenoid is involved with adducting the arytenoid cartilage and closing the rima glottidis.

Question 8

The right ansa cervicalis is anastomosed with the right recurrent laryngeal nerve to reinnervate the muscles of the larynx and restore phonation. Which muscles will be paralyzed?

Answer 8

The ansa cervicalis innervates the strap muscles, including the sternohyoid, sternothyroid and omohyoid muscles.

Question 9

A patient has lost sensation from over the angle of the jaw. Which nerve is injured?

Answer 9

The area over the angle of the jaw is innervated by the great auricular nerve.

Question 10

A patient’s airway is obstructed and a midline tracheostomy inferior the thyroid isthmus is performed. Which vessels are most likely to be present at the site of incision?

Answer 10

The structures below the isthmus of the thyroid gland would be the inf. thyroid vein and the thyroidea ima artery.

Question 11

A patient has a hoarse voice and has difficulty breathing on exertion. Which nerve was most likely injured?

Answer 11

The recurrent laryngeal nerve is the most likely nerve damaged because it runs in close proximity to the inf. thyroid artery.

The recurrent laryngeal nerve innervates the majority of the vocal muscles that open and close the rima glottidis, in addition to providing sensory supply to the larynx below the vocal folds.

Question 12

A patient’s tongue deviated toward the right side when she was asked to protrude it. Which nerve was injured?

Answer 12

The hypoglossal nerve provides innervation to all muscles of the tongue except the palatoglossus (CN X). Injury to the hypoglossal nerve would result in deviation of the tongue toward the affected side when the tongue is protruded, due mainly to the unilateral contraction of the left genioglossus.

Question 13

After a thyroidectomy, a patient frequently aspirated fluid into her lungs. It was determined that the area of the piriform recess above the vocal fold ot he larynx was anesthetized. Which nerve is injured?

Answer 13

The internal branch of the superior laryngeal nerve was injured. Injury to this nerve results in loss of sensation above the vocal cords at the entrance to the larynx and loss of taste on the epiglottis.

Question 14

What is the only muscle of the larynx that abducts the vocal cords?

Answer 14

The posterior cricoarytenoids

Question 15

describe the function and innervation of the cricothyroid muscle

Answer 15

The function is to increase the pitch of phonation and is the only laryngeal muscle supplied by the external branch of the superior laryngeal nerve (as opposed to the recurrent laryngeal).

Question 16

Otoscopic examination reveals fluid in the middle ear cavity. Hypertrophy of which stricture would compromise the drainage of the auditory tube?

Answer 16

The pharyngeal tonsil is found in the pharyngeal recess in the nasopharynx behind the opening of the audtory tube. A pharygeal tonsil in this location can lead to blockage of the drainage of the auditory tube.

Question 17

A patient lost the ability to notice the presence of foreign objects in the laryngeal vestibule. Which nerve was injured?

Answer 17

The internal laryngeal nerve (off the superior laryngeal nerve) supplies sensation to the larynx above the vocal cords. Loss of sensation would result in an inability to detect food or foreign objects in the laryngeal vestibule.

Question 18

Name the branches and functions of the superior laryngeal nerve

Answer 18

The superior laryngeal nerve has 2 branches:

1. internal laryngeal nerve
   
   • supplies sensation to the larynx above the vocal cords
2. external laryngeal nerve
   
   • innervates the cricothyroid muscles that aids in changing the pitch of phonation

Question 20

If a particular nerve is injured bilaterally, there is significant risk of asphyxiation unless the patient is intubated. Which muscle pairs opens the airway?

Answer 20

The posterior cricoarytenoid muscle (innervated by the recurrent laryngeal n.) is the only abductor of the larynx that opens the rima glottidis.

Question 21

Which artery supplies most the blood to the palatine tonsils?

Answer 21

The palatine tonsils are highly vascular and are primarily supplied by the tonsillar branch of the facial artery.

Question 22

describe the lymph drainage above the vocal cords, the middle of the vocal cords and below the vocal cords

Answer 22

• above vocal cords = superior deep cervical nodes
• middle = very little direct lymph drainage from this region
• below vocal cords = pretracheal nodes -> inf. deep cervical nodes

Question 23

During an emergency cricothyroidotomy an artery is accidentally injured. 2 days later the patient shows signs of aspiration pneumonia. Which artery was most likely injured?

Answer 23

The cricothyroid artery is a small branch of the sup. thyroid artery. It anastomoses with the cricothyroid artery of the opposite side at the upper end of the median cricothyroid ligament, a common site for establishing an emergency airway.

The cricothyroid artery can be pushed into the airway during the procedure. The vessel can bleed directly into the trachea and cause fatal aspiration of blood.

Question 24

A patient has dysphagia, nighttime fits of coughing, repeated chest infxns, and a palpable swelling in the neck. Examination reveals the presence of a persistent congenital pharyngeal pouch. Between which muscles is the pouch located?

Answer 24

The pharyngeal (Zenker’s) diverticulum is usually located between the cricopharyngeal and thyropharyngeal portions fo the inf. pharyngeal constictor.

Question 25

Which nerve supplies general sensation to the mucous membrane of the laryngeal vestibule and piriform recesses?

Answer 25

The internal branch of the sup. laryngeal n. supplies the mucosa of the larynx above the vocal folds (which includes the vestibule of the larynx) and the piriform recess.

The external branch of the sup. laryngeal nerve is motor to the cricothyroid muscle.

Question 26

Which nerve coursing along the tonsillar bed needs to be spared during surgery?

Answer 26

The glossopharyngeal n. is located in the tonsillar bed as it runs with the stylopharyngeus muscle which it innervates.

Question 27

Which muscle functions to open the rima glottidis?

Answer 27

The function of the cricoarytenoid muscle is to abduct the vocal cords.

Transverse arytenoid and lateral cricoarytenoid muscle adducts the vocal cods.

Cricothyroid lengthen the vocal cords and thyroarytenoid muscles narrow the laryngeal cavity.

Question 28

Damage to the left external laryngeal nerve will result in what?

Answer 28

There would be monotone and easily fatigued voice with poor pitch control

Question 29

A patient has their uvula deviated to the right. When the left side of the pharyngeal mucosa is touched, the gag reflex is weaker than when the mucosa on the right side is touched. Which nerve is injured?

Answer 29

The vagus nerve is responsible for innervation to the soft palate; if damaged, the uvula would deviate from the side of the lesion.

Question 30

what are the afferent/efferent limbs of the cough reflex?

Answer 30

The vagus does both, the afferent and efferent limbs of the cough reflex

Question 31

What are the landmarks for a cricothyrotomy?

Answer 31

The cricothyroid membrane, which is located between the thyroid cartilage and the cricoid cartilage below

Question 32

The superior thyroid artery is ligated and special attention needs to be paid to the adjacent nerve. Which muscle is innervated by this nerve?

Answer 32

The superior thyroid artery, superior thyroid vein and external branch of the superior laryngeal nerve course together in a neruovascular triad that originates superior the thyroid gland and lateral to the thyroid cartilage.

The external branch of the superior laryngeal nerve innervates the cricothyroid muscle.