H&N Oropharynx anatomy

Question 1

What head and neck subsite is defined by the posterior pharyngeal wall, lateral pharyngeal constrictors, superiorly by the hard palate, inferiorly by the vallecula and hyoid bone, and anteriorly by the circumvallate papilla and palatoglossal muscles?

Answer 1

Oropharynx

Question 2

What are the anatomical subsites of the orophar-

ynx, and how are they defined?

Answer 2

● Tonsil: Bordered by the anterior and posterior tonsillar
pillars, glossotonsillar sulcus, confluence of the soft
palate and tonsillar pillars, and superior pharyngeal
constrictor muscle
● Base of tongue: Circumvallate papillae anteriorly,
glossotonsillar sulci laterally, hyoid bone/floor of the
vallecula inferiorly
● Soft palate: Hard palate anteriorly, palatopharyngeus
muscle and uvula posteriorly, superior constrictor muscle
laterally, confluence of the anterior and posterior tonsillar
pillars inferiorly and nasopharynx superiorly
● Posterior oropharyngeal wall: Level of the hyoid bone/floor of vallecula inferiorly, soft palate superiorly, posterior tonsillar pillars and piriform sinuses laterally
* Most commonly involved subsites

Question 3

What anatomical site is considered a part of the
oropharynx and is defined as the space anterior to
the lingual/oropharyngeal surface of the epiglottis,
posterior to the base of tongue, medial to the

glossoepiglottic fold and piriform sinus, and superficial to the hyoepiglottic ligament (which denotes the superior extent of the pre-epiglottic space)?

Answer 3

Vallecula

Question 4

Lymphatic tissue of the nasopharynx and oropharynx, including the pharyngeal tonsil, palatine
tonsil, and lingual tonsil, constitute what important complex?

Answer 4

Waldeyer ring

Question 5

What anatomical structures enter the pharynx
between the superior and middle pharyngeal
constrictor muscles, just inferior to the tonsil?

Answer 5

Stylopharyngeus muscle, styloglossus muscle, stylohyoid

ligament, glossopharyngeal nerve (CN IX).

Question 6

What important fascial layer separates the tonsillar

region from the parapharyngeal space?

Answer 6

Buccopharyngeal fascia.

Question 7

Name the layers of the posterior pharyngeal wall.

Answer 7

Mucosa → superior pharyngeal constrictor muscle →
buccopharyngeal fascia → retropharyngeal space (contains
lateral fat pads and retropharyngeal nodes) → alar fascia →
prevertebral fascia → prevertebral muscles (laterally)/
anterior longitudinal ligament (medially) → vertebral bodies

Question 8

Name the muscular components of the soft palate

and their innervation.

Answer 8

● Superior pharyngeal constrictor muscle (CN IX, X)
● Palatopharyngeus muscle (CN X)
● Palatoglossus muscle (CN X)
● Tensor veli palatini muscle (CN V3)
● Levator veli palatini muscle (CN X)
● Uvular muscle (CN X)

Question 9

Describe the arterial supply to each oropharyngeal

subsite.

Answer 9

External carotid system:
● Tonsil: Tonsillar branch of the ascending pharyngeal
artery, descending palatine artery, tonsillar branch of the
facial artery,* dorsal lingual artery, and ascending
palatine artery
● Base of tongue: Lingual artery* and its branches (supra-
hyoid branch, dorsal lingual artery, and arteria profunda
linguae)
● Soft palate: Lesser palatine artery,* ascending pharyngeal
artery, tonsillar branches from the dorsal lingual artery,
ascending palatine artery
● Posterior pharyngeal wall: Ascending pharyngeal artery*
* Denotes primary arterial supply.

Question 10

Describe the location of the internal carotid artery

in relationship to the tonsil.

Answer 10

● Posterolateral to the lateral oropharyngeal wall
● Separated from tonsil by superior constrictor and
buccopharyngeal fascia
● On average, it is 1.4 cm from the tonsillar fossa in a 1-
year-old and 2.5 cm in an adult.

Question 11

Describe the venous outflow from the oropharynx.

Answer 11

Drains to the jugular venous system:
● Tonsil: Tonsillar and pharyngeal plexus, lingual and facial
veins
● Base of tongue: Lingual and retromandibular veins
● Soft palate: pharyngeal and pterygoid plexus, external
palatine vein
● Posterior pharyngeal wall: pharyngeal venous plexus

Question 12

What nerve is at risk during base of tongue
surgery if resection of the hyoglossus muscle to
the level of the hyoid bone is required?

Answer 12

Hypoglossal nerve

Question 13

Which nerves supply the pharyngeal plexus?

Answer 13

Vagus nerve (CN X), glossopharyngeal nerve (CN IX), and
sympathetic fibers from the superior cervical ganglion

Question 14

Which lymph node basins are common sites of spread

of oropharyngeal carcinoma?

Answer 14

Levels II, III, and IV most commonly

Question 15

In addition to levels II, III, and IV, what other lymph
node group is at risk with tonsil, soft palate, and
posterior pharyngeal wall cancer?

Answer 15

Retropharyngeal nodes

Question 16

Why do tumors of the base of tongue have a high

risk of bilateral nodal disease?

Answer 16

Precollecting lymphatic channels on each side cross the
midline to drain to the contralateral side (up to 30% at
presentation). Level II is at highest risk for bilateral disease.

Question 17

Describe the three lymphatic systems associated

with the soft palate.

Answer 17

● Medial → middle one-third of the jugular chain (level III)
● Lateral → retropharyngeal lymph nodes
● Anterior → hard palate → submental and submandibular
nodes (levels IA and IB)
Note: Uvular lymphatics drain primarily to level IIA.

Question 18

Describe the lymphatic drainage of the posterior

pharyngeal wall.

Answer 18

Retropharyngeal nodes (up to 44%), levels II and III