Posterior urethral valves
 Discussion of Posterior urethral valves
- Posterior urethral valves are the most common congenital obstructive lesion of the urethra, occurring only in phenotypic boys.
- Posterior urethral valves result from the formation of a thick, valvelike membrane from tissue of wolffian duct origin that courses obliquely from the verumontanum to the most distal portion of the prostatic urethra. The valve is a diaphragm, but because it is more rigid along its line of fusion, progressive distention during voiding causes it to become bilobed or sail-like.
 Imaging Findings for Posterior urethral valves
- VCUG is the best imaging technique for the diagnosis of posterior urethral valves.
- Radiologic findings include dilatation and elongation of the posterior urethra and, occasionally, a linear radiolucent band corresponding to the valve.
- Vesicoureteral reflux occurs in 50% of patients.
- Bladder trabeculation, hypertrophy, and diverticula are also demonstrated at VCUG (any cause of bladder outlet obstruction such as posterior urethral valves will cause bladder trabeculation or wall thickening).
 See Also
 External Links
 References for Posterior urethral valves
- Teresa Berrocal, Pedro López-Pereira, Antonia Arjonilla, and Julia Gutiérrez. Anomalies of the Distal Ureter, Bladder, and Urethra in Children: Embryologic, Radiologic, and Pathologic Features. RadioGraphics 2002 22: 1139-1164.