In this photo we are measuring post residual void using rehabilitative ultrasound in our office! Post residual void is the amount of urine left in your bladder after you have urinated. Believe it or not there usually is a small amount of urine left in the bladder after emptying it, which is considered normal. In other words, it does not completely empty when you urinate. The volume of post residual void which is normal in patients over 65 is less than 50 mL; less than 100 mL is considered acceptable, but is considered abnormal in younger patients. Patients sometimes feel bladder pressure, the need to void twice, and may be more susceptible to urinary tract infections and have pelvic pain if the bladder is not able to fully empty. A full bladder can hold about 600 ml of urine but we usually get the urge to go at about 150ml. Higher amounts of post residual void (referred to as bladder retention) can occur because of an obstruction in the urinary tract, such as an enlarged prostate or bladder stones, swelling of the urethra or bladder from infections, nerve problems, medications, pelvic floor muscle over-activity, pelvic organ prolapse, postpartum, constipation, urethral stricture, or a weak detrusor muscle (the name of the bladder muscle). But bearing down chronically to push out urine is not a good idea and can lead to other problems. Once we determine that urinary retention is occurring we refer the patient back to the urologist or urogynecologist for further assessment. Our treatment approach is then geared to helping this problem by way of manual therapies, visceral mobilization, bladder/bowel retaining, toilet posture, pelvic floor muscle rehab, surface EMG pelvic floor muscle biofeedback, and behavioral modification. Together with your physician we help you achieve your rehab goals.