Stenosis of the External Urethral Orifice in the Boy vs. Urethral Diverticulum
Left picture: The reason for the difficulties of micturation is a severe stenosis of the external urethral orifice, caused by a xerotic balanitis. Notice in the x-ray the sudden decrease in the urethral calibre at the anterior end of the urethra. Right picture: Here, the disorders of micturation is caused by a small diverticulum of the urethra which is lying anteriorly from the distal urethra, and fills during micturation, thereby hindering further micturation due to the compression of the urethra by the diverticulum at the same level. Notice the conically ending urethra and the elongated contrast accumulation underneath the supposed distal urethra which is separated from a structure running parallel without contrast(= anterior urethral wall). In this VCUG, as well as in that of the contralateral patient, the external sphincter muscle is indirectly visible.
Left picture: 13.11-year-old boy with difficulties with micturation such as delay of the beginning of micturation, requirement of strong pressing, thin urinary stream, and terminal dribbling of urine. The urethra is enlarged in the VCUG along its whole length. Right picture: VCUG in a toddler with a thin and weak urinary stream. After micturation starts the child has difficulties keeping up the stream, and there is terminal dribbling. The whole urethra is dilated.