The anatomy of the levator ani muscle was studied in relation to the urinar
y bladder. The study was performed on 23 cadavers by dissection and microsc
opic examination. The levator ani is funnel-shaped and consists of a transv
erse portion called the levator plate and a vertical portion called the sus
pensory sling. The levator plate is a cone and consists of two "lateral mas
ses" and two "crura," with the levator hiatus occupying its anterior part.
Three crural patterns could be identified: classic, crural overlap, and cru
ral scissors. The levator crura are connected to the intrahiatal organs by
the hiatal ligament, the pubovesical ligament constitutes the anterior part
of this ligament. The suspensory sling forms a vertical cuff around the in
trahiatal organs, from which it is separated by a "tunnel septum." Its uret
hral portion ends in multiple fibrous septa, which penetrate the striated u
rethral sphincter. The levator ani plays an important role in bladder-neck
fixation provided by the suspensory sling and hiatal ligament. Levator ani
and hiatal ligament subluxation leads to ptosis of the urinary bladder. Fur
thermore, the present study demonstrates that the urethra is located in the
infralevator compartment and is thus protected from the effect of intraabd
ominal pressure. A chronic increase in intraabdominal pressure leads to lev
ator subluxation and sagging and to urethral exposure to intraabdominal pre
ssure, which seems to interfere with the micturition mechanism. The infrale
vator location of the urethra might have a bearing on the pathogenesis and
treatment of stress urinary incontinence.