Relationships between urethrovesical angles and urinary incontinence due to urethral sphincter mechanism incompetence in bitches.

In women, the posterior urethrovesical angle is thought to be an important factor in the aetiology of stress urinary incontinence. This form of incontinence has many similarities to urethral sphincter mechanism incompetence (SMI) in the bitch. The role of the ventral and dorsal urethrovesical angles in the aetiology of SMI in the incontinent bitch has yet to be established. Positive-contrast retrograde vagino-urethrograms from 30 incontinent bitches with a diagnosis of SMI and 30 continent bitches were retrieved and the angles between the urethra and dorsal and ventral bladder walls were measured. No relationship was shown to exist between the dorsal urethrovesical angle (the equivalent of the posterior urethrovesical angle in women) and urinary incontinence due to SMI in bitches. Differences in ventral urethrovesical angles were considered to be associated with differences in bladder neck position between the two groups of bitches.