中年男性尿道括约肌复合体磁共振成像的解剖研究

Anatomy on Magnetic Resonance Imaging of Urethral Sphincter Complex in Middle-aged Males

目的利用磁共振成像(magnetic resonance imaging,MRI)研究中年男性尿道括约肌复合体的正常解剖形态。方法对106例正常控尿的中年男性尿道括约肌复合体进行MRI观察,在仰卧位静息态,获取盆腔矢状面、冠状面和横截面的T2加权快速自旋回波图像。结果尿道括约肌复合体由尿道平滑肌和尿道外括约肌组成。尿道平滑肌于后侧终止于会阴体,于前面止于阴茎白膜,于两侧向远端走行止于两侧坐骨支。尿道外括约肌包括尿道横纹括约肌与尿道平滑括约肌,尿道横纹括约肌于膀胱颈及膜部最厚,在膀胱颈处形成完整的环,在膜部尿道,尿道横纹括约肌呈“戒指”状包绕尿道,向后与会阴中心腱相连,向远端止于阴茎白膜。正中矢状面图像能够测量尿道横纹括约肌长度:膜部尿道处长度为12.13~20.86 mm,平均16.86 mm;自精阜至会阴膜长度为27.65~30.88 mm,平均28.67 mm。横断面图像能够测量膜部尿道横纹括约肌厚度,前壁肌层厚度为4.08~6.58 mm,平均5.38 mm,后壁肌层厚度为2.06~2.25 mm,平均2.18 mm。结论MRI能够清楚观察到中年男性尿道括约肌复合体的解剖结构,是观察男性尿道括约肌复合体解剖结构较理想的影像学方法。

Objective To study the anatomy on magnetic resonance imaging(MRI)of urethral sphincter complex in middle-aged males.Methods The sagittal,coronal,and axial T2-weighted non-fat suppressed fast spin-echo images of pelvic cavities of 106 middle-aged males were studied.Results The urethral sphincter complex consisted of urethral smooth sphincter and striated(external)urethral sphincter.The urethral smooth muscle extended down the urethra,forward to be connected with tunica albuginea penis and backward to be connected with perineal body and ambilateral to be connected with ramus ossis ischii.The external urethral sphincter consisted of transverse sphincter of urethra and smooth sphincter of urethra.The transverse sphincter of urethra was the thickest in bladder neck and membranous part,forming a complete ring at bladder neck.In membranous part of urethra,the transverse sphincter of urethra encircled urethra in a ring shape,connecting with central perineal tendon backward,and ending at tunica albuginea distally.The median sagittal plane image could measure the length of transverse striated sphincter:the length of membranous urethra was 12.13-20.86 mm,with an average of 16.86 mm;The length from seminal caruncle to perineal membrane was 27.65-30.88 mm,with an average of 28.67 mm.The thickness of transverse striated sphincter of membranous urethra could be measured by cross-sectional images.The thickness of anterior wall muscle layer was 4.08-6.58 mm,with an average of 5.38 mm,and the thickness of posterior wall muscle layer was 2.06-2.25 mm,with an average of 2.18 mm.Conclusion The anatomy of urethral sphincter complex in middle-aged males can be seen clearly on MRI,which is an ideal image method for study and clinical practice of male urethral sphincter complex.