H&N 10: The Pharynx

Question 1

What are the divisions of the pharynx?

Answer 1

Nasopharynx, oropharynx, laryngopharynx

Question 2

Where does the nasopharynx run from and to?

Answer 2

From the base of the skull to the upper border of the soft palate

Question 3

What is contained within the nasopharynx?

Answer 3

Pharyngeal tonsil (adenoids) and orifice of the Eustachian tube

Question 4

Where does the oropharynx run from and to?

Answer 4

From the soft palate to the superior border of the epiglottis

Question 5

What is contained within the oropharynx?

Answer 5

The palatine tonsils between the palatoglossal (anterior) and palatopharyngeal (posterior) arches

Question 6

Where does the laryngopharynx run from and to?

Answer 6

From the epiglottis to the oesophagus (at the level of the inferior border of the cricoid cartilage)

Question 7

What is contained in the laryngopharynx?

Answer 7

A small depression called the piriform fossa (common site for food and foreign bodies to become stuck)

Question 8

Which vertebrae love posterior to each section of the pharynx?

Answer 8

C1 posterior to nasopharynx
C2,3 posterior to oropharynx
C4,5,6 posterior to laryngopharynx

Question 9

What are the internal muscles of the pharynx, and their innervation?

Answer 9

Stylopharyngeus, CN IX
Palatopharyngeus, CN X
Salpingopharyngeus, CN X

Question 10

What is the function of the internal muscles of the pharynx?

Answer 10

To shorten and widen the pharynx and elevate the larynx during swallowing

Question 11

What are the external muscles of the pharynx, and their innervation?

Answer 11

Superior, middle and inferior circular muscles
All innervated by the vagus nerve

All contract peristaltically to push bolus into oesophagus

Question 12

What is the common tendinous origin of the external circular pharynx muscles?

Answer 12

Pharyngeal raphe

Question 13

What is Killian’s dehiscence?

Answer 13

A small area of weakness between the two muscle belly components of the inferior constrictor

If pharynx is incoordinated during swallowing/ UOS fails, part of the pharyngeal mucosa can herniate through Killian’s dehiscence to form the pharyngeal pouch. Food can trap here -> dysphagia, bad breath, choking

Question 14

What is the innervation of the muscles of the pharynx?

Answer 14

All vagus nerve innervated, except the stylopharyngeus which is innervated by glossopharyngeal nerve

Question 15

What is the sensory innervation of the areas of the pharynx?

Answer 15

Nasopharynx: CNV2
Oropharynx: CN IX
Laryngopharynx: CN X

Question 16

What are the stages of swallowing?

Answer 16

1. Oral
   Voluntary, makes the bolus and pushes it to oropharynx
2. Pharyngeal
   Involuntary, soft palate elevated to seal off nasopharynx (opens ET), epiglottis closes over larynx, bolus moves through pharynx by contractions of constrictors, relaxation of UOS, supra hyoid muscles elevate pharynx and larynx
3. Oesophageal
   Involuntary, into GI system

Question 17

What are some causes of dysphagia?

Answer 17

Stroke/ dementia/ Parkinson’s

Question 18

Which tonsils swell in tonsillitis?

Answer 18

Palatine tonsils

Question 19

Which lymph nodes will swell in tonsillitis?

Answer 19

Jugulodigastric

Question 20

What is Waldeyer’s tonsillar ring?

Answer 20

A ring of lymphoid tissue consisting of pharyngeal tonsil, palatine tonsils and lingual tonsils

Question 21

What are the suprahyoid muscles?

Answer 21

• 4 pairs of strap like muscles that all elevate the hyoid bone during swallowing
• stylohyoid, geniohyoid, digastric, mylohyoid

Question 22

What are the infra hyoid muscles?

Answer 22

4 muscles that act to depress the hyoid bone
In the superficial plane: sternohyoid and omohyoid
(Both innervated by anterior rami of C1-3, branch of ansa cervicalis)

In the deep plane: sternothyroid and thyrohyoid
Sternothyroid innervated by anterior rami of C1-3
Thyrohyoid innervated by anterior rami of C1, within hypoglossal nerve

Question 23

Where is the thyroid gland?

Answer 23

In the anterior neck, between C5 and T1
2 lobes that are connected by an isthmus
Wraps around the cricoid cartilage, and lies inferior to the thyroid cartilage of the larynx
Bound to the pretracheal fascia along with trachea, oesophagus and pharynx

Question 24

What is the vascular supply of the thyroid gland?

Answer 24

2 paired arteries on both the left and right

Superior thyroid artery (first branch of ECA) supples superior and anterior

Inferior thyroid artery (from thyrocervical trunk) supples posterior and inferior

Question 25

What is the venous drainage of the thyroid veins?

Answer 25

Superior and middle thyroid veins drain into internal jugular veins
Inferior thyroid veins drains into brachiocephalic vein

Question 26

What is the course of the recurrent laryngeal nerves?

Answer 26

Left and right, both arise from their respective vagus nerves and descend into the chest

RRL nerve hooks around subclavian artery
LRL nerve hooks around the arch of aorta

Then ascend back up the neck, between the trachea and oesophagus and underneath the thyroid gland to innervate the larynx

(Care must be taken during thyroid gland surgery not to ligate the RL nerves)

Question 27

What would uvula and soft palate deviation towards the right hand side be suggestive of?

Answer 27

Implies a weakness of the muscles on the left side
Majority of soft palate muscles are vagus nerve innervated
So implies a lesion of the left vagus nerve

Question 28

Where are the deep cervical lymph nodes located?

Answer 28

Deep to the SCM
Closely associated with the carotid sheath and IJV

(Deep cervical lymph nodes = Jugulodigastric, jugulo-omohyoid, supra clavicular)