Thirty-two female patients with clinical and urodynamic findings of genuine 
stress urinary incontinence were evaluated before and 6 months after surgery for 
stress urinary incontinence. Twenty-nine control patients had identical 
evaluations before and 6 months after surgery which did not involve the 
urethrovesical junction. Twenty-four patients with primary bladder instability 
had similar evaluations and served as a second control group. Anatomical 
landmarks indicating support to the urethrovesical junction were evaluated by 
the position of the urethra at the most dependent point in the bladder on 
straining and the urethral descent on straining to beneath the posterior ramus 
of the symphysis pubis on bead chain cystography. The urethrovesical junction 
drop on straining was evaluated by transrectal ultrasonography. Cystographic and 
ultrasonographic tests for the position of the urethrovesical junction at the 
most dependent position in the bladder during straining were very sensitive in 
women with stress urinary incontinence (94 and 87% respectively) but much less 
specific (45 and 48% respectively). When evaluating anatomical support to the 
urethrovesical junction and its descent on straining, these tests were both 
highly sensitive (97 and 94% respectively) and specific (76 and 96% 
respectively) in women with genuine stress urinary incontinence. Simple clinical 
tests for support of the urethrovesical junction, such as the Q tip test, are 
non-specific in patients with stress urinary incontinence. Transrectal 
ultrasonography is a simple and quick out-patient procedure. The availability of 
ultrasound equipment in most clinics and the high sensitivity and specificity of 
the test make it an attractive and cost-effective alternative to X-ray 
cystography in the pre-operative evaluation of anatomical support to the 
urethrovesical junction.