H&N hypopharynx anatomy

Question 1

What are the anatomical boundaries of the

hypopharynx?

Answer 1

● Superior: Hyoid bone/floor of vallecula, pharyngoepiglot-
tic folds
● Inferior: Plane at the lower border of the cricoid cartilage;
esophageal introitus or cricopharyngeus muscle
● Anterior: Junction of the pyriform sinuses in the post-
cricoid region
● Posterior: Level of the superior surface of the hyoid bone/
floor of the vallecula to the inferior border of the cricoid
cartilage and from the apex of one piriform sinus to the
other

Question 2

Which paired subsite of the hypopharynx extends
from the pharyngoepiglottic fold to the upper end of
the esophagus or lower border of the cricoid cartilage
and is referred to as an inverted pyramid (base at
pharyngoepiglottic fold, apex at level of cricoid)?

Answer 2

Pyriform sinus

Question 3

What subsite of the hypopharynx extends from
the level of the superior surface of the hyoid bone
or floor of the vallecula to the inferior border of
the cricoid cartilage and from the apex of one
piriform sinus to the other?

Answer 3

Posterior hypopharyngeal wall

Question 4

What subsite of the hypopharynx extends from
the anterior hypopharyngeal wall from below the
posterior arytenoid cartilage to the inferior border
of the cricoid cartilage?

Answer 4

Postcricoid area

Question 5

What subsite forms a transition point between the
supraglottis and hypopharynx, is considered a part
of the supraglottis, and often results in aggressive
disease when involved by tumors?

Answer 5

“Marginal area”: Lateral wall of the aryepiglottic folds

Question 6

What is the distribution of hypopharyngeal tumors

arising in the three subsites?

Answer 6

Varies geographically. In the United States: Pyriform sinus
(up to 86%) > posterior pharyngeal wall (10 to 23%) > post-
cricoid area (less than 5%). In Egypt: Postcricoid area
(50.1%) > pyriform sinus (26.5%) > posterior pharyngeal wall
(23.4%)

Question 7

Between the area of transition of the inferior pharyngeal constrictor muscle and the cricopharyngeus muscle is a potential area of weakness and spread of posterior hypopharyngeal wall
tumors beyond the hypopharynx. What is the name of this area?

Answer 7

Killian triangle

Question 8

What is the arterial supply to the hypopharynx?

Answer 8

● External carotid artery:
● Superior laryngeal artery*
● Branches of the lingual artery
● Branches of the ascending pharyngeal artery
*Denotes primary blood supply; venous drainage is through
the pharyngeal plexus, adjacent named veins, and jugular
system.

Question 9

Describe the sensory and motor innervation of the

hypopharynx.

Answer 9

● Sensory: Glossopharyngeal (IX) and vagus (X) nerves via
the pharyngeal plexus; additionally, sympathetics from
the pharyngeal plexus may also contribute.
● Motor: Vagus (X) nerve via pharyngeal plexus

Question 10

Which aerodigestive tract primary site has the

highest prevalence of cervical nodal metastasis?

Answer 10

Hypopharynx (approximately 70%)

Question 11

What is the primary lymphatic drainage of the

hypopharynx?

Answer 11

Primarily drain to levels II–IV, also level VI (especially with
inferior hypopharyngeal and post cricoid disease). Other
nodal basins at risk include retropharyngeal nodes.