Further Studies on the Trigone Muscle: The Anatomy And Practical Considerations

Abstract

The fibers of the trigonal muscle of the female bladder lie beneath the mucous membrane of the trigone, and run from each ureteral orifice, over the trigone and internal sphincter to the urethra, upon the posterior wall of which they terminate. Some of these fibers also pass between the two ureteral orifices.The internal sphincter of the bladder consists of an inner and an outer portion. The inner portion is composed of an internal ring of fibers and the external partial ring. The outer portion of the sphincter is composed of fibers which form partial loops around the internal fibers and then become continuous with the bladder musculature. The external sphincter muscle surrounds the membranous urethra and consists of inner circular and outer transverse fibers. The cystoscopic examinations of similar cases parallel the anatomic dissections.