In direct laryngoscopy which of the following cannot be visualized

Following structures are examined serially: Base of tongue, right and left valleculae, epiglottis, (its tip, lingual and laryngeal surfaces), right and left pyriform sinuses,aryepiglottic folds, arytenoids, postcricoid region, both false cords, anterior and posterior commissure, right and left ventricles, right and left vocal cords and subglottic area. Mobility of vocal cords should also be observed. Ref: Dhingra 7e pg 481.