Burnett A L, Mostwin J L
Department of Urology, Johns Hopkins University School of Medicine, James Buchanan Brady Urological Institute, Johns Hopkins Medical Institutions, Baltimore, Maryland, USA.
J Urol. 1998 Oct;160(4):1301-6.
We describe a correlative gross anatomical and histological study of the human male urethral sphincteric complex using methods that delineate skeletal, muscular and fascial components.
Pelves of 6 fresh frozen male cadavers were sectioned as 4 mm. tissue blocks in planes sagittal and perpendicular to the axis of the prostatomembranous urethra from the bladder neck to the bulb of the corpus spongiosum. Sections were photographed and prepared in situ for histological staining (hematoxylin and eosin, Masson's trichrome and phosphotungstic acid hematoxylin).
The structure of the male urethral sphincteric complex was demonstrated to include the cylindrical rhabdosphincter surrounding the prostatomembranous urethra and a fascial framework, principally consisting of the ventral subpubic fascia and medial fascia of the levator ani musculature. The histological appearance of the rhabdosphincter at its dorsal aspect suggested a suburethral musculofascial plate. Rhabdosphincteric muscle fibers were oriented in vertical and ventrolateral directions with attachments to the subpubic fascia and the medial fascia of the levator ani.
The structural components and their relationships suggest mechanisms whereby the complex is suspended and stabilized within the deep pelvis, and achieves urethral closure. Our study furthers an understanding of the anatomical basis for male urinary continence and micturition, and is expected to have primary importance in the effort to preserve urinary function following major pelvic surgery.
