Role of pelvic floor in lower urinary tract function

The pelvic floor plays an integral part in lower urinary tract storage and evacuation. Normal urine storage necessitates that continence be maintained with normal urethral closure and urethral support. The endopelvic fascia of the anterior vaginal wall, its connections to the arcus tendineous fascia pelvis (ATFP), and the medial portion of the levator ani muscles must remain intact to provide normal urethral support. Thus, normal pelvic floor function is required for urine storage. Normal urine evacuation involves a series of coordinated events, the first of which involves complete relaxation of the external urethral sphincter and levator ani muscles. Acquired dysfunction of these muscles will initially result in sensory urgency and detrusor overactivity; however, with time the acquired voiding dysfunction can result in intermittent urine flow and incomplete bladder emptying, progressing to urinary retention in severe cases. This review will start with a discussion of normal pelvic floor anatomy and function. Next various injuries to the pelvic floor will be reviewed. The dysfunctional pelvic floor will be covered subsequently, with a focus on levator ani spasticity and stress urinary incontinence (SUI). Finally, future research directions of the interaction between the pelvic floor and lower urinary tract function will be discussed.