Anatomy of the Pharynx

Question 1

Describe the pharynx?
Histology?

Answer 1

• About 13 cm long
• Post to mouth
• Common passage for respiratory & digestive systems
• Both mouth & pharynx are lined with stratified squamous epithelium

Question 2

What are fauces?

Answer 2

opening between oral cavity & pharynx

Question 3

The pharynx is divided into?

Answer 3

Nasopharynx
Oropharynx
Laryngopharynx

Question 4

What are the functions of the pharynx?

Answer 4

deglutition or swallowing
respiration

Question 5

Describe the boundaries of the pharynx?

Answer 5

1. Superior - body of sphenoid & occipital bones
2. Posterior - buccopharyngeal & prevertebral fascia, pharyngeal constrictor muscles, C1-C6
3. Lateral - stylopharyngeus muscle, medial pterygoid muscle, carotid sheath, thyroid gland
4. Anterior - continuous with nasal & oral cavities and larynx
5. Inferior - esophagus

Question 6

Describe the location and function of the nasopharynx?

Answer 6

Post to nose & sup to soft palate
Has a respiratory function

Question 7

Describe the innervation of the nasopharynx?

Answer 7

Anterosuperior portion of nasopharynx
> maxillary nerve
Nasopharynx distal to ostium (opening) of auditory tube & rest of pharynx
> glossopharyngeal & vagus nerves

Question 8

What is a pharyngeal tonsil?

Answer 8

Lymphoid tissue associated with mucous membrane of post & sup nasopharynx

Question 9

What is an adenoid?

Answer 9

enlargement of the pharyngeal tonsil
> common in children
> may produce nasal obstruction
> ear or sinus infections
> difficulty breathing
> Treatment = antibiotics

Question 10

What is the pharyngotympanic tube?

Answer 10

connects the nasopharynx to middle ear
> is marked by torus tubarius: circular terminal end of auditory tube’s cartilage

Question 11

What is the the function of the pharyngotympanic tube?

Answer 11

When open, it equilibrates pressure within the middle ear with that of pharynx

Question 12

What are the clinical correlates for the pharyngotympanic tube?

Answer 12

the Potential path for the spread of infection from pharynx to middle ear

Question 13

When is the pharyngotympanic tube open or closed?

Answer 13

Cartilaginous portion of tube is closed or opened upon swallowing or yawning - contraction of tensor veli palatini muscle

Question 14

What is the location and function of the oropharynx?

Answer 14

Soft palate to top of epiglottis
Has a digestive function

Question 15

Describe the boundaries of the oropharynx?

Answer 15

1. Sup by soft palate
2. Inf by base of tongue
3. Lat by palatoglossal & palatopharyngeal arches
   > palatine tonsil - lymphoid tissue - Tonsillectomy
4. Posterior wall is anterior to the prevertebral fascia, pharyngeal constrictor muscles, C2 & C3 vertebrae

Question 16

What is the location of the larygopharynx?

Answer 16

superior border of epiglottis to esophagus

Question 17

What are the boundaries of the laryngopharynx?

Answer 17

1. Anteriorly - laryngeal inlet
2. Posteriorly - musculofascial wall & C4-C6 vertebrae
3. Lateral to laryngeal inlet - piriform recesses (site for lodged foreign bodies or swallowed pills)
4. Inferiorly, laryngopharynx narrows - cricopharyngeal sphincter of esophagus

Question 18

Name the muscles of the pharynx?

Answer 18

1. Pharyngeal constrictor circular muscles
   > Superior, middle & inferior pharyngeal constrictors
2. Longitudinally oriented muscles
   > Palatopharyngeal & stylopharyngeus muscles

Question 19

Describe the function of the pharyngeal constrictor circular muscles of the pharynx?

Answer 19

action - constricts pharynx, tone aids in maintaining wall
sphincter function - at laryngopharyngeal & esophageal junction

Question 20

Describe the action of the longitudinally oriented muscles of the pharynx?

Answer 20

• elevate pharynx & larynx
• shorten pharynx during swallowing or speaking

Question 21

Describe the arterial supply of the pharynx?

Answer 21

Ascending pharyngeal artery
Superior and inferior thyroid arteries
Ascending & descending palatine arteries
Lingual artery

Question 22

Describe the venous drainage of the pharynx?

Answer 22

pharyngeal venous plexus

Question 23

Describe the lymphatic drainage of the pharynx?

Answer 23

tonsillar nodes (jugulodigastric) nodes

Question 24

Describe the innervation of the pharynx?

Answer 24

Pharyngeal plexus arising from the vagus nerve
Superior cervical sympathetic ganglion
Maxillary nerve
Glossopharyngeal nerve
Internal laryngeal nerve
Recurrent laryngeal nerve

Question 25

What is swallowing/deglutition?

Answer 25

mechanical and physiological act of moving food/fluid from oral cavity to stomach
- Deglutition is divided into 3 stages

Question 26

Describe the first stage of deglutition?

Answer 26

voluntary
follows mastication
mouth is closed & breathing is temporarily interrupted
bolus is formed using contraction of mylohyoid & styloglossus muscles & intrinsic muscles of tongue - elevating tongue against palate

Question 27

Describe the second stage of swallowing?

Answer 27

Passage of bolus through the pharynx
involuntary
stimulation of sensory receptors at the opening of oropharynx
pressure of tongue against hard palate seals nasopharynx from oral cavity
This creates pressure that forces bolus into orophaynx
Soft palate & uvula are elevated to close nasopharynx as bolus passes
Hyoid bone & larynx also elevated
Elevation of larynx against epiglottis seals glottis preventing bolus entry into trachea
Sequential contraction of constrictor muscles moves bolus through pharynx to esophagus

Question 28

Describe the third stage of deglutition?

Answer 28

entry & passage of food through the esophagus
Involuntary
Bolus is moved through the esophagus
peristalsis

Question 29

What is Transsphenoidal pituitary hypophysectomy?

Answer 29

gaining access to a pituitary adenoma through nasopharynx

Question 30

What are infected adenoids?

Answer 30

may produce nasal obstruction