Ureteral ostium

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The ureteral orifice (v. Lat. Ostium , input 'and ureter , the ureter '; also ureteral orifice , ureteral or ureteral orifice ), the paired entry site of the urethra into the bladder .

Anatomical location and function

The orifices of the ureter, together with the starting area of ​​the urethra , the urinary bladder fundus ( ostium urethrae internum ), delimit the trigonum vesicae (urinary bladder triangle). The distance between the two ureter openings on the plica interureterica (ureteral ridge) is normally 40 to 50 mm in an adult. The last section of the ureter runs in the urinary bladder wall. The orifices of the ureter are therefore normally closed when the bladder is full and therefore tense. If this occlusion is incomplete for genetic or acquired reasons, it can lead to vesicoureteral reflux , which means that urine flows back from the urinary bladder via the ureters into the renal pelvis. Among other things, this can lead to repeated bacterial infections, such as pyelonephritis (inflammation of the kidney pelvis). The ability of the ureteral ostia to close can be checked with the help of a micturition cystourethrogram .

Anomalies of the ureteral ostia

Normal ureter orifices appear oval or slit-shaped on urethrocystoscopy (urethral and bladder endoscopy). They then lie on the interureteric plica . Abnormal ureter openings are divided into different types of shape and location. The normal position is called trigonal (type A). Deviations in position extend to type D, which is strongly lateralized. There is the pronounced oval mouth (with the shape of a stadium), which is usually offset to the side (laterally). The horseshoe-shaped ostium is usually even more lateralized and often leads to vesicoureteral reflux because of the shorter intramural tunnel. Urinary reflux can also occur with a circular ostium ("golf hole"). This type often develops after resection of a bladder tumor on or in the ostium.

An opening of one or both ureters into the urethra is known as an ectopic ureter . This malformation is hereditary in dogs .

Individual evidence

  1. ↑ D. Thüer: Zystoskopische Leitstruktur . In: S. Wille, A. Heidenreich (Hrsg.): Atlas of diagnostic endourology. Georg Thieme Verlag, 2009, ISBN 3-131-43471-6 , p. 26. Restricted preview in the Google book search
  2. ↑ E. Bücheler, KJ Lackner, M. Thelen: Introduction to Radiology: Diagnostics and Interventions. Georg Thieme Verlag, 2006, ISBN 3-133-16011-7 , p. 583. Restricted preview in the Google book search
  3. ^ S. Wille: Anomalies of the ureter ostia. In: S. Wille, A. Heidenreich (Hrsg.): Atlas of diagnostic endourology. Georg Thieme Verlag, 2009, ISBN 3-131-43471-6 , pp. 44-46. limited preview in Google Book search

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