Which of the following part is NOT included in hypopharynx -

Which of the following part is NOT included in hypopharynx -

1.pyriform sinus
2.post cricoid region
3.anterior pharyngeal wall
4.Posterior pharyngeal wall

explanation

Clinically, hypopharynx is subdivided into three regions :-
The pyriform sinus
Post-cricoid region
The posterior pharyngeal wall