Which of the following is NOT a pa of hypopharynx

HYPOPHARYNX or (LARYNGOPHARYNX) Clinically, hypopharynx is subdivided into three regions--the pyriform sinus, postcricoid region and the posterior pharyngeal wall. 1. Pyriform sinus (fossa):- It lies on either side of the larynx and extends from pharyngoepiglottic fold to the upper end of oesophagus. It is bounded laterally by the thyrohyoid membrane and the thyroid cailage and medially by the aryepiglottic fold, posterolateral surfaces of arytenoid and cricoid cailages. It forms the lateral channel for food. Foreign bodies may lodge in the pyriform fossa. Internal laryngeal nerve runs submucosally in the lateral wall of the sinus and thus is easily accessible for local anaesthesia. It is also through this nerve that pain is referred to the ear in carcinoma of the pyriform sinus. 2. Postcricoid region:- It is the pa of the anterior wall of laryngopharynx between the upper and lower borders of cricoid lamina. It is a common site for carcinoma in females suffering from Plummer-Vinson syndrome. 3. Posterior pharyngeal wall:- It extends from the level of hyoid bone to the level of cricoarytenoid joint. Ref:- Dhingra; pg num:-241