Normal anatomy of urethral sphincter complex in young Chinese males on MRI.

PURPOSE: In this research, the normal anatomy of urethral sphincter complex in young Chinese males has been studied.

METHODS

The sagittal, coronal, and axial T2-weighted non-fat suppressed fast spin-echo images of pelvic cavities of 86 Chinese young males were studied.

RESULT: Urethral sphincter complex is a cylindrical structure surrounding the urethra and extending vertically from bladder neck to perineal membrane. Urethral striated sphincter covers the anteriolateral urethra like a hat from bladder neck to verumontanum, while it surrounds the urethra in a ring shape from verumontanum to perineal membrane and backwards ends in central tendon of the perineum. From bladder neck to perineal membrane, the thickness of urethral smooth sphincter decreases gradually, and it extends forward to surround urethra with urethral striated sphincter as a ring. The length of urethral striated sphincter is 12.26-20.94 mm (mean 16.59 mm) at membranous urethra: 27.88-30.69 mm (mean 28.99 mm) from verumontanum to perineal membrane. The thickness of striated sphincter at membranous urethra is 4.29-6.86 mm (mean 5.56 mm) for the muscle of the anterior wall and 2.18-2.34 mm (mean 2.26 mm) for the muscle of the posterior wall.

CONCLUSIONS

In this paper, we summarized the normal anatomy of urethral sphincter complex in young Chinese males with no urinary control problems.