10.2 Pharynx

Question 1

Where is the pharynx located?

Answer 1

Cranial Base to the
Inferior Border of the Cricoid Cartilage Anteriorly
Inferior Border of C6 Vertebra Posteriorly.

Question 2

Where is the pharynx widest and narrowest?

Answer 2

Widest (Approximately 5cm) opposite the hyoid.

Narrowest (approximately 1.5cm) at its inferior end, where it is continuous with the oesophagus.

Question 3

Borders, epithelium, function and contents of nasopharynx.

Answer 3

Posterior to nose, superior to the soft palate.

Pseudostratified ciliated columnar with goblet cells
Stratified squamous epithelium

Respiratory function - posterior extension of nasal cavities via chonae, conditioning inspired air and propagating to larynx.

Lymphoid tissue in Waldeyer’s ring
Adenoids
Eustachian tube orifice

Question 4

Borders, vertebral level, epithelium, function and contents of oropharynx.

Answer 4

Soft palate to the superior border of the epiglottis.

C2/C3

Stratified squamous non-keratinised

Digestive
Voluntary and involuntary phase of swallowing.

Posterior 1/3 of tongue
Lingual tonsils
- Inferiorly to tongue
Palatine tonsils
Superior pharyngeal constrictor

Question 5

Where are the palatine tonsils found?

Answer 5

Oropharynx between palatoglossal and palatopharyngela arches.

Question 6

What is the blood supply to the palatine tonsils?

Answer 6

ECA - maxillary - facial - tonsillar

Pharyngeal venous plexus

Question 7

What is the venous drainage of the palatine tonsils?

Answer 7

Jugulodigastric node
At angle of mandible
Enlarged in tonsilitis

Question 8

Borders, vertebral level, epithelium, function and contents of laryngopharynx.

Answer 8

Superior border of the epiglottis –> Inferior border to cricoid cartilage.
Becomes continuous with oesophagus
Communicates with larynx via laryngeal inlet.

C3-C6

Stratified squamous non keratiniesed

Middle and inferior pharyngeal constrictors.

Question 9

What forms the wall of the pharynx?

Answer 9

Outer circular muscle layer
Inner longitudinal muscle layer

Covered internally by pharyngobasilar fascia and mucous membrane.

Question 10

What innervates the muscles of the pharynx?

Answer 10

Outer muscle layer and inner muscle layer innervated by CNX except stylopharyngeus (CNIX)

Question 11

What forms the outer circular muscular layer, function, innervation?

Answer 11

Layers stacked like glasses - open anteriorly

Superior Constrictor
- Found in oropharynx

Middle Constrictor
- Found in the laryngopharynx

Inferior Constrictor

• Found in the larygopharynx
• Superior component (thyropharyngeus) has oblique fibres that attach to the thyroid cartilage.
• Lower horizontal fibres known as Cricopharyngeus that attach to the cricoid cartilage.

Contract sequentially from superior to inferior to constrict the lumen and propel the bolus of food into the oesophagus.

CNX

Question 12

What are the two components of the inferior constrictor muscle?

Answer 12

Thyropharyngeus (oblique fibres to thyroid cartilage)

Cricopharyngeus (horizontal fibres to the cricoid cartilage)

Question 13

Where does the outer muscular layer attach?

Answer 13

Posteriorly to the midline rap he
Incomplete anteriorly
Overlap inferior over superior.

Question 14

What are the three muscles of the inner longitudinal layer?

Answer 14

Stylopharyngeus CNIX

Palatopharyngeus CNX

Salpingopharyngeus CNX

Question 15

What do the inner longitudinal muscles do during swallowing?

Answer 15

Shorten and widen the pharynx

Salpingopharyngeus opens the Eustacian tube to equalise middle ear pressure.

Question 16

Sensory innervation of pharynx

Answer 16

Nasopharynx - CNV1/CNV2
Oropharynx CNIX
LAryngopharynx - CNX

Question 17

Vertebral levels of bony landamarks

Answer 17

C1 - Hard palate
C2 - angle of mandible
C3 - hyoid bone
C4/C5 - thyroid cartilage
C6 - cricoid cartilage

Question 18

3 phases of swallowing

Answer 18

1. Voluntary
2. Pharyngeal
3. Oesophageal

Question 19

What occurs in voluntary phase

Answer 19

Tongue retracts, pushing bolus of food to oropharynx.

Question 20

What occurs in pharyngeal phase

Answer 20

Pressure receptors in palate and pharynx stimulate swallow centre
Inhibition of breathing
Raising of larynx by supra hyoids (stabilised by infra hyoids)
Closure of glottis
Opening of upper oesophageal sphincter.
Contraction of pharyngeal constrictor muscles sequentially from the superior to inferior

Question 21

What occurs in oesophageal phase?

Answer 21

Muscles in upper 1/3 = striated
Muscles in lower 2/3 = smooth involuntary
Peristalisis wave spreads along oesophagus propelling bolus down to stomach in 9 seconds.
Lower oesophageal sphincter opens.

Question 22

Why does the thyroid elevate in swallowing?

Answer 22

Thyroid gland is attached to the hyoid bone so elevated with they laryngeal skeleton during swallowing. The inferior thyroid artery from the thyrocervical trunk is tortuous to allow extension when the thyroid moves up.

Question 23

Blood supply to pharynx?

Answer 23

ECA - Maxillary - Facial
ECA - Lingual
ECA - Superior thyroid artery
ECA - Ascending pharyngeal

Question 24

Venous drainage of pharynx?

Answer 24

Pharyngeal plexus - IJV

Question 25

Afferent and efferent of gag reflex?

Answer 25

Stimulation of oropharynx
CNIX
CNX

Question 26

Where are adenoids? When are they largest? When do they enlarge?

Answer 26

Lymphatic tissue collection
Found at junction of roof and posterior wall of nasopharynx
Largest from 3-8yo, regress
Enlarge with viral and bacterial URTI
Recurrent infection - chronically enlarged

Question 27

Clinical features of nasal obstruction?

Answer 27

Mouth breathing
Nasal speech
Feeding difficulty
Snoring / Obstructive sleep apnoea
Chronic otitis media with effusion.

Question 28

Risk of tonsillectomy?

Answer 28

Rutpure of tonsillar branch of facial artery

ICA or CNIX

Question 29

What is quinsy? Treatment?

Answer 29

Peritonsillary abscess - infection spreads to peritonsillar tissue forming pus filled lesion.
Deviation of uvula - quinsy
Requires drainage and antibiotics

Question 30

Common site for food to become stuck in pharynx?

Answer 30

Vallecula
Mucosa pouch bewteen tongue and epiglottis
Piriform fossa
Mucousal recess between central larynx and lateral lamina of thyroid cartilage

Question 31

Describe pharyngeal pouch.

Answer 31

Inferior pharyngeal constrictor = thyropharyngeus and cricopharyngeus
In normal swallwoing, thyropharyngeus contracts as cricopharyngeus relaxes allowing propulsion of bolus into oesophagus without raising intrapharyngeal pressure.
If coordinated relaxation of cricopharyngeus does not occur, intrapharyngeal pressure rises, and mucosa forms a midline diverticulum where food can accumulate.