<prompt> Killians dehiscence is seen in:OropharynxNasopharynxCricopharynxVocal cords  <response>: Ans. c Cricopharynx. Ref. Diseases of ENT by PL Dhingra, 3rd pg. 290 Inferior constrictor muscle has two parts:- Thyropharyngeus oblique fibers- Cricopharyngeus transverse fibers Between these two parts exists a potential gap, known as Killans dehiscence gateway of tears. Clinical significance:- Perforation during esophagoscopy- Pharyngeal pouchPHARYNGOESOPHAGEAL DIVERTICULUM ZENKER DIVERTICULUM General Considerations- Zenker diverticulum originates from the posterior wall of the esophagus, in a triangular area of weakness limited:SS inferiorly by the cricopharyngeus muscle andSS superiorly by the inferior constrictor muscles ie, the Killian triangle.- As the diverticulum enlarges, it tends to deviate from the midline, mostly to the left. Pathogenesis- Zenker diverticulum results from either a lack of coordination between the pharyngeal contraction and the opening of the UES or a hypertensive UES.- Because of the increased intraluminal pressure, there is progressive herniation of mucosa and submucosa through the Killian triangle.Clinical Findings - Essentials of Diagnosis- Dysphagia, the most common symptom- Regurgitation of undigested food with risk of aspiration.- Gurgling sounds in the neck.- Halitosis. Imaging Studies- A barium swallow is the investigation of choice. It can also show a hiatal hernia. Treatment- The standard treatment consists of excision of -the diverticulum and myotomy of the cricopharyngeus muscle, including the upper 3 cm of the posterior esophageal wall.- For small diverticula ie, 2 cm, myotomy alone is sufficient. As an alternative to the conventional treatment, a transoral endoscopic approach, using an endoscopic stapling instrument, can be used for diverticula between 3 cm and 6 cm in size. Prognosis- The prognosis is excellent in about 90 of cases. 