A cystometrogram tests the pressure inside the bladder. It helps your doctor find out whether your bladder is contracting (squeezing) on its own and if so, how well. It also measures how much urine your bladder can hold. Your doctor uses this information to help figure out the correct bladder management program for your spinal cord injury.

A small catheter is placed in your bladder and connected to a machine. The machine will insert water or carbon dioxide gas into your bladder. You will tell your doctor when you can feel your bladder beginning to fill or other bladder pressure. Your doctor will also want to know when you feel you have to urinate and when you can no longer "hold it." At the same time, your bladder pressure and how much your bladder can hold is measured and put on a graph.