OBG510 — Urogynaecology: Lecture Note

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This is the complete lecture note for OBG510 Urogynaecology. You can read it online below, open it in the full viewer, or download the PDF for offline study. It pairs with the course's video lectures, so you can read and watch together.

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la-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS

la-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS Course code: OBG 510 Course title: Urogynaecology Course credit load: 1 Unit Series 1: Anatomy and Physiology of the Urogenital System • Part 1.1: Anatomy of the Lower Urinary Tract o Sub Part 1.1.1: Anatomy of the bladder and urethra o Sub Part 1.1.2: Anatomy of the ureters o Sub Part 1.1.3: Blood supply, innervation, and lymphatic drainage of the lower urinary tract • Part 1.2: Anatomy of the Pelvic Floor and Support System o Sub Part 1.2.1: The pelvic floor musculature o Sub Part 1.2.2: The pelvic support system o Sub Part 1.2.3: Relationship between the urogenital and genital tracts • Part 1.3: Physiology of Micturition o Sub Part 1.3.1: Bladder filling and storage o Sub Part 1.3.2: Neural control of micturition o Sub Part 1.3.3: Normal voiding and common terminology Introduction Picture a woman describing a symptom she has been too embarrassed to mention for months, urine leaking when she coughs or laughs. Understanding why this happens, and how to help her, begins with a genuinely solid grasp of the anatomy and physiology of the urogenital system, the bladder, urethra, ureters, and the pelvic floor and support structures that hold everything in its correct place. This Series lays that essential foundation for the whole of this course on urogynaecology, before we turn in later Series to the specific disorders, fistulae, and prolapse conditions that arise when this normally elegant system is disrupted. The aim of this Series is to equip you with a thorough understanding of the anatomy of the urogenital system, the pelvic floor and support system, and the physiology of micturition.

la-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS We shall commence this Series by examining the anatomy of the lower urinary tract, including the bladder, urethra, and ureters. Next, we will consider the anatomy of the pelvic floor and support system, and its relationship to the genital tract. Finally, we will conclude by examining the physiology of micturition and common urogynaecological terminology. Series Learning Outcomes Upon completing this Series, you should be able to: • SLO 1.1: describe the anatomy of the bladder and urethra, • SLO 1.2: describe the anatomy of the ureters and their relationship to pelvic structures, • SLO 1.3: describe the blood supply, innervation, and lymphatic drainage of the lower urinary tract, • SLO 1.4: describe the pelvic floor musculature and the pelvic support system, • SLO 1.5: describe the relationship between the urogenital and genital tracts, • SLO 1.6: describe the physiology of bladder filling, storage, and neural control of micturition, and • SLO 1.7: describe normal voiding and common urogynaecological terminology. 1.1 Anatomy of the Lower Urinary Tract 1.1.1 Anatomy of the bladder and urethra The urinary bladder is a hollow, muscular organ situated in the pelvis anterior to the uterus and vagina in the female, composed of the detrusor muscle (a layer of smooth muscle responsible for bladder contraction during voiding), lined internally by transitional epithelium, and possessing a trigone, a triangular area at the base of the bladder defined by the two ureteric orifices and the internal urethral orifice, anatomically and functionally distinct from the remainder of the bladder wall. The female urethra is considerably shorter than the male urethra, measuring approximately three to four centimetres in length, extending from the bladder neck to the external urethral meatus, surrounded by the urethral sphincter mechanism, itself comprising both an internal, smooth muscle component under autonomic control and an external, striated muscle component under voluntary control, together genuinely essential for maintaining urinary continence.

la-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS Fill in the blank: The trigone is a triangular area at the base of the bladder defined by the two ureteric orifices and the internal ________ orifice. The female urethra measures approximately three to ________ centimetres in length. 1.1.2 Anatomy of the ureters The ureters are paired, muscular tubes conveying urine from the renal pelvis to the bladder, descending retroperitoneally through the abdomen and pelvis, with the pelvic portion of particular surgical relevance in gynaecological practice given its close anatomical proximity to the uterine artery, where the ureter passes beneath the artery at a point sometimes described as 'water under the bridge', a relationship of genuine practical importance in avoiding inadvertent ureteric injury during pelvic surgery. The ureter enters the bladder obliquely through the bladder wall, a specific anatomical arrangement creating a functional valve mechanism that prevents retrograde flow of urine from the bladder back into the ureter during bladder filling and voiding, an elegant, purely anatomical solution to preventing vesicoureteric reflux without requiring any specific, discrete anatomical valve structure. Fill in the blank: The ureter passes beneath the uterine artery at a point sometimes described as 'water under the ________'. The ureter enters the bladder obliquely, creating a functional valve mechanism preventing ________ flow of urine. 1.1.3 Blood supply, innervation, and lymphatic drainage of the lower urinary tract The bladder receives its principal blood supply from the superior and inferior vesical arteries, branches of the internal iliac artery, with venous drainage via a corresponding vesical venous plexus, while innervation is genuinely complex, combining sympathetic fibres (promoting bladder filling and storage by relaxing the detrusor and contracting the internal sphincter) and parasympathetic fibres (promoting bladder emptying by contracting the detrusor and relaxing the internal sphincter). The external urethral sphincter is innervated by the pudendal nerve, providing voluntary control over urinary continence, with lymphatic drainage of the bladder passing principally to the external and internal iliac lymph nodes, an anatomical relationship of genuine relevance when considering the staging and surgical management of bladder malignancy, though genuinely less immediately relevant to the majority of benign urogynaecological conditions covered throughout the remainder of this course. Fill in the blank: Sympathetic innervation promotes bladder filling and storage by relaxing the detrusor and contracting the internal ________. The external urethral sphincter is innervated by the ________ nerve, providing voluntary control over continence.

la-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS Figure 1.1: Anatomy of the female lower urinary tract and the ureter-uterine artery relationship. Pilot questions 1.1 1. Describe the anatomy of the bladder, including the trigone. (Linked to SLO 1.1) 2. Describe the anatomy and sphincter mechanism of the female urethra. (Linked to SLO 1.1) 3. Describe the course of the ureter and its relationship to the uterine artery. (Linked to SLO 1.2) 4. Explain the mechanism preventing vesicoureteric reflux. (Linked to SLO 1.2) 5. Describe the blood supply and innervation of the bladder. (Linked to SLO 1.3)

la-NET | ONLINE LEARNING VIDEO PLATFORM FOR POST-SECONDARY & HIGHER INSTITUTION STUDENTS 1.2 Anatomy of the Pelvic Floor and Support System 1.2.1 The pelvic floor musculature The pelvic floor is formed principally by the levator ani muscle group (comprising the pubococcygeus, puborectalis, and iliococcygeus muscles), together forming a genuinely essential muscular sling supporting the pelvic organs, the urethra, vagina, and rectum passing directly through this specific muscular structure as it descends from the bony pelvis to the perineum. Adequate pelvic floor muscle tone and function is genuinely essential for maintaining both urinary and faecal continence and for supporting the pelvic organs against the downward pressure exerted by intra-abdominal pressure, with damage or weakening of this muscular support, whether from childbirth, chronic straining, or age-related change, directly contributing to the development of both pelvic organ prolapse and urinary incontinence discussed throughout the remainder of this course. Fill in the blank: The pelvic floor is formed principally by the levator ani muscle group, comprising the pubococcygeus, puborectalis, and ________ muscles. Damage or weakening of pelvic floor support directly contributes to pelvic organ prolapse and urinary ________. 1.2.2 The pelvic support system The pelvic support system combines the muscular pelvic floor with the endopelvic fascia (a connective tissue network) and specific ligamentous structures, including the cardinal and uterosacral ligaments (providing lateral and posterior support to the upper vagina and cervix), together forming a genuinely integrated system of support that, when functioning normally, maintains the pelvic organs in their correct anatomical position. The concept of three anatomical levels of vaginal support (level I, apical support from the cardinal-uterosacral ligament complex; level II, lateral support of the mid-vagina from the paravaginal attachments; and level III, distal support of the lower vagina and perineal body) provides a genuinely useful, structured anatomical framework for understanding the specific pattern of support loss underlying different types of pelvic organ prolapse. Fill in the blank: The cardinal and uterosacral ligaments provide lateral and posterior support to the upper vagina and ________. Level I vaginal support refers to apical support from the cardinal-________ ligament complex. 1.2.3 Relationship between the urogenital and genital tracts The close anatomical proximity between the urogenital and genital tracts in the female pelvis, with the bladder and urethra anteriorly, the uterus and vagina centrally, and the rectum posteriorly, all genuinely intimately related and, in places,

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