The levator ani muscles and their fascia have been generally conceded to be the essential supports of the urinary bladder.
Cystocele has been recognized to be a true hernia of the bladder—more specifically, a herniation of the fundus and trigon, which are those parts in association with the anterior vaginal wall.
The degree of incontinence of urine is evidently dependent on whether there is a urethrocele, which may or may not be associated with a cystocele, and varies enormously in different cases. It has been generally accepted that the specific anatomic lesion responsible for the incontinence is relaxation of "the sphincter muscle," yet most physicians have had a rather vague picture of the sphincteric anatomy and a very meager knowledge of the physiologic mechanism of vesical control.
The modern conception of correction of a cystourethrocele with incontinence has been that of repair of a hernia, with reenforcement of the urethral
CURTIS AH, ANSON BJ, McVAY CB. ANATOMIC FACTORS IN PATHOGENESIS AND TREATMENT OF URETHROCELE AND CYSTOCELE. JAMA. 1938;111(10):903–906. doi:10.1001/jama.1938.02790360011003