title: 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.
authors.affiliation: Department of Anatomy, College of Medical and Dental Sciences, University of Birmingham, Birmingham, B15 2TT, United Kingdom.
authors.forename: Adarsh P
authors.initials: AP
authors.lastname: Shah
authors.forename: Amit
authors.initials: A
authors.lastname: Mevcha
authors.forename: Daniel
authors.initials: D
authors.lastname: Wilby
authors.forename: Anton
authors.initials: A
authors.lastname: Alatsatianos
authors.forename: John C
authors.initials: JC
authors.lastname: Hardman
authors.forename: Steven
authors.initials: S
authors.lastname: Jacques
authors.forename: Joanne C
authors.initials: JC
authors.lastname: Wilton
mesh_terms: D006801:Humans; D007001:Hypogastric Plexus / Q000033:anatomy & histology / Q000503:physiopathology*; D017773:Pelvic Floor / Q000033:anatomy & histology / Q000294:innervation / Q000503:physiopathology*; D060525:Pudendal Nerve / Q000033:anatomy & histology / Q000503:physiopathology*; D014521:Urethra / Q000033:anatomy & histology / Q000294:innervation / Q000503:physiopathology*; D001743:Urinary Bladder / Q000033:anatomy & histology / Q000294:innervation / Q000503:physiopathology*; D014549:Urinary Incontinence / Q000503:physiopathology*; D014554:Urination / Q000502:physiology*; D019459:Urothelium / Q000294:innervation / Q000503:physiopathology*
keywords: levator ani; micturition; pudendal nerve; urinary incontinence; urothelium