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Posterior urethral valve (PUV) disorder is an obstructive developmental anomaly in the urethra and genitourinary system of male newborns. A posterior urethral valve is an obstructing membrane in the posterior male urethra as a result of abnormal ''in utero'' development. It is the most common cause of bladder outlet obstruction in male newborns. The disorder varies in degree, with mild cases followed conservatively. More severe cases can have renal and respiratory failure from lung underdevelopment as result of low amniotic fluid volumes, requiring intensive care and close monitoring.〔(【引用サイトリンク】Emedicine - Posterior urethral valves - overview and treatment. )〕 Incidence is one in 8000 babies.〔(【引用サイトリンク】Posterior urethral valves - Disease Information. )〕 ==Classification== Posterior urethral obstruction was first classified by H. H. Young in 1919. The ''verumontanum'', or mountain ridge, is a distinctive landmark in the prostatic urethra, important in the systemic division of posterior valve disorders: * Type I - Most common type; due to anterior fusing of the ''plicae colliculi'', mucosal fins extending from the bottom of the verumontanum distally along the prostatic and membranous urethra〔(【引用サイトリンク】Nationwide Children's Hospital, Radiology - Posterior urethral valves )〕 * Type II - Least common variant; vertical or longitudinal folds between the verumontanum and proximal prostatic urethra and bladder neck * Type III - Less common variant; a disc of tissue distal to verumontanum, also theorized to be a developmental anomaly of congenital urogenital remnants in the bulbar urethra Researchers have suggested that obstructions in the posterior urethra are more appropriately termed congenital obstructions of the posterior urethral membrane (COPUMs). The congenital urothelial remnants of type III posterior urethral valves have been eponymously referred to as Cobb's collar or Moorman's ring.〔(【引用サイトリンク】Nationwide Children's Hospital, Radiology - Cobb's Collar )〕 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「Posterior urethral valve」の詳細全文を読む スポンサード リンク
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