Pharynx + Larynx

Question 1

What are the 3 divisions of the pharynx?

Answer 1

Nasopharynx
Oropharynx
Laryngopharynx

Question 2

Where is the nasopharynx located?

Answer 2

Anterior border = Continuous with the nasal cavity
Posterior border = C1 vertebral body
Inferior border = Lower body of soft palate

Question 3

What are the functions of the larynx?

Answer 3

Primary: protect the tracheobronchial tree
Prevents inhalation of food/liquids (aspiration)
Enables phonation

Question 4

What nerve supplies motor innervation to the larynx?

Answer 4

Recurrent laryngeal branch (of CNX) - all laryngeal muscles except the cricothyroid which is innervated by the superior laryngeal nerve (branch of CN X)

Question 5

What is the function of the lateral cricoarytenoid muscles?

Answer 5

Internal rotation of the arytenoid cartilage and adduction of the vocal cords to protect airways by preventing aspiration

Question 6

What is the function of the posterior cricoarytenoid muscles?

Answer 6

Abduction and external rotation of the arytenoid cartilage to open vocal cords for breathing

Question 7

What nerve supplies sensory innervation to the larynx?

Answer 7

Above vocal folds = superior laryngeal (CN X)

Below vocal folds = recurrent laryngeal (CN X)

Question 8

What might be the consequence of unilateral or bilateral damage to the superior laryngeal nerve supply?

Answer 8

Loss of sensation above vocal folds

Inability to depress thyroid cartilage - low pitch voice

Question 9

What might be the consequence of a unilateral loss of recurrent laryngeal nerve supply?

Answer 9

Flaccidity to ipsilateral vocal fold - can be asymptomatic or have some voice disturbance (hoarseness) but little effect on respiratory system

Question 10

What might be the consequence of a bilateral loss of recurrent laryngeal nerve supply?

Answer 10

Severe stridor/ impaired breathing

Hoarse voice

Question 11

What is the arterial supply to the larynx?

Answer 11

Superior laryngeal (branch of superior thyroid) 
Inferior laryngeal (branch of inferior thyroid)

Question 12

Why is the cricothyroid ligament clinically relevant?

Answer 12

Can be incised in emergency situations to insert tracheostomy tube when there is an obstruction in the larynx (or above) and intubation has been unsuccessful

Question 13

What anatomical feature prevents food from entering our nasal cavity?

Answer 13

Soft palate muscles close communication between the nasopharynx and oropharynx when eating:

Tensor Veli Palatini (stretches palate)
Levator Veli Palatini (lifts palate)

Question 14

How does epithelium change as you move down the pharynx?

Answer 14

Transitions from pseudostratified ciliated columnar epithelium to stratified squamous epithelium

Question 15

What are the borders of the oropharynx?

Answer 15

From the upper border of the soft palate to the lower border of the epiglottis

Question 16

What are the borders of the laryngopharynx?

Answer 16

Base of tongue/upper epiglottis to the cricopharyngeus muscle

Question 17

What is the sensory nerve innervation to the pharynx?

Answer 17

Nasopharynx = CN Vb + CN IX 
Oropharynx = CN IX 
Laryngopharynx = CN IX + CN X

Question 18

What 3 muscles make up the pharynx?

Answer 18

Superior, middle and inferior constrictors (lined by continuous internal fascia and mucosa)

Question 19

What does contraction of the pharynx muscles result in?

Answer 19

Reduce diameter of pharynx tube to squeeze food down (by peristalsis)

Question 20

What might damage to the vagus nerve result in?

Answer 20

Dysphagia
Risk of aspiration (which can lead to pneumonia)
Compromised gag reflex

Question 21

What is Eagle syndrome?

Answer 21

Unusually long styloid processes causing difficulty swallowing and the feeling of something in throat (caused by bone sticking into soft muscle)

Question 22

Where is the ‘weak spot’ in the pharynx and what may be the clinical consequence of this?

Answer 22

Gap between muscle fibres of the inferior constrictor muscle and the cricopharyngeus
Potential point of herniation of pharyngeal tissue

Question 23

What is the midline Raphe?

Answer 23

Posterior attachment point for constrictor muscles - extends from the base of the skull to the ‘weak spot’

Question 24

What is a normal swallowing process?

Answer 24

1. Coordinated peristalsis of constrictors
2. Relaxation of cricopharyngeus muscle
3. Drop in intrapharyngeal pressure to allow food to progress downwards

Question 25

What is a Zenker diverticulum?

Answer 25

Posteriorly herniated pharyngeal lining at ‘weak spot’ forming pouch where food can get stuck
Can result in halitosis and coughing up of old food

Question 26

What is the function of the thyroarytenoid muscle?

Answer 26

Relaxes the vocal cords during speech to lower pitch

Question 27

What is the motor innervation to the muscles of the pharynx?

Answer 27

All CN X innervated except:

Tensor Veli Palatini - CN Vc
Stylopharyngeus - CN IX