Yucel Selcuk, Baskin Laurence S
Department of Urology and Pediatrics, UCSF Children's Medical Center, University of California San Francisco, 94143, USA.
J Urol. 2004 May;171(5):1890-7. doi: 10.1097/01.ju.0000124106.16505.df.
We performed a detailed study of the lower urinary tract of the male and female human fetus to elucidate the anatomy of the urethral sphincter complex in both sexes and its relationship to the surrounding organs and tissues.
A total of 12 male and 14 female normal human pelvic specimens ranging from 17.5 to 38 weeks of gestation were studied by serial sections and immunohistochemical analysis. Three-dimensional reconstructions were created from serial sections to demonstrate the anatomy of the lower urogenital tract and urethral sphincter in both sexes. Specific attention was directed to the sphincteric muscle of the urethra.
The urinary continence mechanism is formed by a combination of detrusor, trigone and urethral sphincter muscles with distinctive histological characteristics in both sexes. In males the external urethral sphincter covers the ventral surface of the prostate as a crescent shape above the verumontanum, horseshoe shape below the verumontanum and crescent shape along the proximal bulbar urethra. The levator ani muscles form an open circle around the external sphincter with a hiatus at the ventral aspect. In females the external urethral sphincter covers the ventral surface of the urethra in a horseshoe shape. Caudally the same horseshoe-shaped external sphincter increases in size to envelop the distal vagina. The levator ani muscles do not support the proximal urethra. The smooth and striated muscle components of the urethral sphincter complex are inseparable in both sexes.
The developmental anatomy of the urethral sphincter complex is analogous in both sexes. The male and female urinary sphincter mechanism is composed of detrusor, trigone and urethral muscles, each of different muscular origins. The levator ani does not surround the ventral aspect of the urethra and may not have an active role in continence in both sexes. This new concept in the anatomy of male and female sphincter morphology may help to refine our reconstructive and ablative surgical techniques.
我们对男性和女性人类胎儿的下尿路进行了详细研究，以阐明两性尿道括约肌复合体的解剖结构及其与周围器官和组织的关系。
通过连续切片和免疫组织化学分析，对12例男性和14例女性正常人类盆腔标本进行了研究，这些标本的孕周为17.5至38周。从连续切片创建三维重建，以展示两性下泌尿生殖道和尿道括约肌的解剖结构。特别关注尿道括约肌。
尿控机制由逼尿肌、三角区和尿道括约肌肌肉组合而成，两性具有独特的组织学特征。在男性中，尿道外括约肌呈新月形覆盖前列腺腹面，在精阜上方，马蹄形在精阜下方，沿近端球部尿道呈新月形。肛提肌围绕外括约肌形成一个开放的环，腹侧有一个裂孔。在女性中，尿道外括约肌呈马蹄形覆盖尿道腹面。在尾侧，同样的马蹄形外括约肌增大以包绕阴道远端。肛提肌不支持近端尿道。尿道括约肌复合体的平滑肌和横纹肌成分在两性中不可分离。
两性尿道括约肌复合体的发育解剖结构相似。男性和女性的尿括约肌机制由逼尿肌、三角区和尿道肌肉组成，各自具有不同的肌肉起源。肛提肌不围绕尿道腹侧，可能在两性尿控中不起积极作用。这种关于男性和女性括约肌形态解剖的新概念可能有助于改进我们的重建和切除手术技术。
