Continence and micturition: An anatomical basis

Abstract

Urinary incontinence remains an important clinical problem worldwide, having a significant socio-economic, psychological, and medical burden. Maintaining urinary continence and coordinating micturition are complex processes relying on interaction between somatic and visceral elements, moderated by learned behavior. Urinary viscera and pelvic floor must interact with higher centers to ensure a functionally competent system. This article aims to describe the relevant anatomy and neuronal pathways involved in the maintenance of urinary continence and micturition. Review of relevant literature focusing on pelvic floor and urinary sphincters anatomy, and neuroanatomy of urinary continence and micturition. Data obtained from both live and cadaveric human studies are included. The stretch during bladder filling is believed to cause release of urothelial chemical mediators, which in turn activates afferent nerves and myofibroblasts in the muscosal and submucosal layers respectively, thereby relaying sensation of bladder fullness. The internal urethral sphincter is continuous with detrusor muscle, but its arrangement is variable. The external urethral sphincter blends with fibers of levator ani muscle. Executive decisions about micturition in humans rely on a complex mechanism involving communication between several cerebral centers and primitive sacral spinal reflexes. The pudendal nerve is most commonly damaged in females at the level of sacrospinous ligament. We describe the pelvic anatomy and relevant neuroanatomy involved in maintaining urinary continence and during micturition, subsequently highlighting the anatomical basis of urinary incontinence. Comprehensive anatomical understanding is vital for appropriate medical and surgical management of affected patients, and helps guide development of future therapies.

Influence of body position on dynamics of the pelvic floor measured with transperineal ultrasound imaging in men

“…As this study only included men with prostate cancer, it is possible that interaction between prostatic tissue and PR influenced our results. As the fibers of PR are contiguous with the prostate, 30 it is possible that cancerous changes to prostatic tissue could influence PR activity and ARJ motion. We cannot exclude the possibility that results would differ for men without prostate disease.…”

Three-dimensional translabial ultrasound assessment of urethral supports and the urethral sphincter complex in stress urinary incontinence

“…Another difference is that we included both the urethral sphincter and the urethral lumen in the measurement of the volume of the USC, as we believe that the lumen is a virtual structure which, except during urination, is collapsed. In addition, both the mucosa and submucosa of the urethra are involved in the intrinsic pressure of the urethra . In view of our results, we can conclude that our assessment of the volume of the USC offers no advantages.…”

Future Perspectives in Bladder Tissue Engineering

“…The lamina propria anchors the urothelium to the detrusor and provides innervation [2]. The detrusor muscle has a rich intramural and superficial vascular network [3]. Both layers must be compliant as the bladder fills in order to facilitate low pressure storage of urine.…”

“…The lamina propria houses vasculature that provides essential oxygen and nutrients to the urothelium, while anchoring it to the bladder muscle [2]. The detrusor muscle facilitates low pressure urine storage and coordinated contractions to expel urine [3]. Individually, the layers serve specific roles; however, taken together, they are all necessary for the unique and essential functions of the bladder.…”