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A Zenker's diverticulum, also pharyngoesophageal diverticulum, also pharyngeal pouch, also hypopharyngeal diverticulum, is a diverticulum of the mucosa of the pharynx, just above the cricopharyngeal muscle (i.e. above the upper sphincter of the esophagus). It is a false diverticulum (not involving all layers of the esophageal wall). It was named in 1877 by German pathologist Friedrich Albert von Zenker.〔F. A. Zenker and Hugo Wilhelm von Ziemssen. Krankheiten des Oesophagus. Leipzig, 1867.〕 == Signs and symptoms == In simple words, when there is excessive pressure within the lower pharynx, the weakest portion of the pharyngeal wall balloons out, forming a diverticulum which may reach several centimetres in diameter. More precisely, while traction and pulsion mechanisms have long been deemed the main factors promoting development of a Zenker's diverticulum, current consensus considers occlusive mechanisms to be most important: uncoordinated swallowing, impaired relaxation and spasm of the cricopharyngeus muscle lead to an increase in pressure within the distal pharynx, so that its wall herniates through the point of least resistance (known as Killian's triangle, located superior to the cricopharyngeus muscle and inferior to the inferior constrictor muscles). The result is an outpouching of the posterior pharyngeal wall, just above the esophagus. While it may be asymptomatic, Zenker diverticulum can present with the following symptoms: * Dysphagia (difficulty swallowing), and sense of a lump in the throat * Food might get trapped in the outpouching, leading to: * * Regurgitation, reappearance of ingested food in the mouth * * Cough, due to food regurgitated into the airway * * Halitosis, smelly breath, as stagnant food is digested by microorganisms * * Infection It rarely, if ever, causes any pain. Cervical webs are seen associated in 50% of patients with this condition. Rarer forms of cervical esophageal diverticula are the Killian's diverticulum and the Laimer's diverticulum. Killian's diverticulum is formed in the Killian-Jamiseon triangle (located inferior to the cricopharyngeus on both sides of this muscle's insertion into the cricoid cartilage). Laimer's diverticulum is formed in Laimer's triangle (located inferior to the cricopharyngeus in the posterior midline above the confluence of the longitudinal layer of esophageal muscle). Laimer's triangle is covered only by the circular layer of esophageal muscle. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Zenker's diverticulum」の詳細全文を読む スポンサード リンク
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