Urinary tract obstruction below the bladder in children can be caused by a posterior urethral valve, as seen in a voiding cystourethrogram. The image shows the spinnaker-sail shape of the valve obstructing the urethra. Distally, the caliber of the bulbous urethra is normal, indicating the obstruction is localized to the valve area.

1. 26Urinary Tract Obstruction
Below the Bladder in Children

2. CLINICAL IMAGAGING
AN ATLAS OF DIFFERENTIAL DAIGNOSIS
EISENBERG
DR. Muhammad Bin Zulfiqar
PGR-FCPS III SIMS/SHL

3. • Fig GU 26-1 Posterior urethral valve. Voiding
cystourethrogram shows the spinnaker-sail
shape of the valve (arrow). Distally, the caliber
of the bulbous urethra is normal.26