The phrase “upside-down, into the void” sums up a report in the BMJ (vol. 328,January 17, 2004, p. 176):
A 67 year old man presented with lower urinary tract symptoms and many episodes of near-acute urinary retention, which he found, by trial and error, he avoided by standing on his head for 5-10 minutes each time his stream was cut off, finding then he was able to void again. X ray examination showed multiple bladder calculi, which undoubtedly obstructed his dependent bladder neck while he was standing but not while he was upside down. At open cystolithotomy more than 300 stones, weighing over 400 g, were removed.
That same section contains a simple, dryly worded nugget of advice for medical diagnosticians:
Computed tomography colonography?or virtual colonoscopy?is gaining ground as a minimally invasive technique for visualising the colon and screening for early neoplasms. Unfortunately, the images of the colon are accompanied by images of the other abdominal organs, bones, blood vessels, and soft tissues. These unwanted data may irritate the clinician, who has no choice but to consider other diagnoses. A study of 75 patients in Denmark (Gut 2003;52: 1744-7) found that 49 had extracolonic abnormalities and 12% needed further investigation. Two patients needed surgery.
Read them both, and see an X-ray of the voiding gentleman, here.