Cystometry is a test that measures the pressure inside of the
bladder to see how well the bladder is working. Cystometry is
done when a muscle or nerve problem may be causing problems with
how well the bladder holds or releases urine. Urination is a
complex process. As the bladder fills, nerves in the bladder
wall send a message to the spinal cord and brain that you need
to urinate. In response, your spinal cord sends a signal for the
bladder to contract (voiding reflex). When you hold in your
urine, your brain is overriding this reflex. When you allow the
reflex to occur, urination occurs. A problem affecting this
nerve pathway or the muscles of the bladder wall can cause
bladder dysfunction. During cystometry, your bladder is filled
with water or gas to measure its ability to hold in and push out
the water or gas. Medicine may also be given to see whether your
bladder contracts or relaxes normally in response to the
medicine. A small tube (catheter) can be placed in your rectum
to measure pressure as the bl