Essentials of Obstetrics PDF 2015

 Essentials of Obstetrics Front Matter.indd 1 19-07-2015 13:00:44 Front Matter.indd 2 19-07-2015 13:00:44  Essentials of Obstetrics Dr Lakshmi Seshadri, md...

 Essentials of Obstetrics Front Matter.indd 1 19-07-2015 13:00:44 Front Matter.indd 2 19-07-2015 13:00:44  Essentials of Obstetrics Dr Lakshmi Seshadri, md Senior Consultant in Obstetrics and Gynecology Thirumalai Mission Hospital, Vellore Formerly, Professor and Head of the Department Christian Medical College Hospital Vellore, Tamil Nadu Dr Gita Arjun, facog Director E. V. Kalyani Medical Foundation Pvt. Ltd. Chennai Formerly, Director, and Obstetrician and Gynecologist E.V. Kalyani Medical Centre Chennai, Tamil Nadu Front Matter.indd 3 19-07-2015 13:00:44  Manager Commissioning: P. Sangeetha Consultant Editor: Dr Vallika Devi Katragadda Production Editor: Pooja Chauhan Asstt Manager Manufacturing: Sumit Johry Copyright © 2015 by Wolters Kluwer Health (India) 10th Floor, Tower C Building No. 10 Phase – II DLF Cyber City Gurgaon Haryana - 122002 All rights reserved. This book is protected by copyright. No part of this book may be reproduced in any form or by any means, including photocopying, or utilized by any information storage and retrieval system with- out written permission from the copyright owner. The publisher is not responsible (as a matter of product liability, negligence, or otherwise) for any injury resulting from any material contained herein. This publication contains information relating to obstetrics and its clinical applications that should not be construed as specific instructions for individual patients. Manufacturers’ product information and package inserts should be reviewed for current information, including contraindications, dosages, and precautions. All products/brands/names/processes cited in this book are the properties of their respective owners. Reference herein to any specific commercial products, processes, or services by trade name, trademark, manufacturer, or otherwise is purely for academic pur- poses and does not constitute or imply endorsement, recommendation, or favoring by the publisher. The views and opinions of authors expressed herein do not necessarily state or reflect those of the publisher, and shall not be used for advertising or product endorsement purposes. Care has been taken to confirm the accuracy of the information presented and to describe generally accepted practices. However, the authors, editors, and publishers are not responsible for errors or omis- sions or for any consequences from application of the information in this book and make no warranty, expressed or implied, with respect to the currency, completeness, or accuracy of the contents of the pub- lication. Application of this information in a particular situation remains the professional responsibility of the practitioner. Readers are urged to confirm that the information, especially with regard to drug dose/ usage, complies with current legislation and standards of practice. Please consult full prescribing informa- tion before issuing prescription for any product mentioned in the publication. The publishers have made every effort to trace copyright holders for borrowed material. If they have inadver- tently overlooked any, they will be pleased to make the necessary arrangements at the first opportunity. First Edition, 2015 ISBN-13: 978-93-5129-443-6 Published by Wolters Kluwer (India) Pvt. Ltd., New Delhi Compositor: Digiprezz Media Solutions, Chennai Printed and bound at Sanat Printers, Haryana For product enquiry, please contact – Marketing Department ([email protected]) or log on to our website www.wolterskluwerindia.co.in. Front Matter.indd 4 19-07-2015 13:00:44  Preface A medical student is on a journey of discovery. Every day of his or her progress through medical educa- tion is crowded with, overwhelming amount of information. The young student struggles hard to not only acquire and assimilate knowledge but also reproduce that knowledge in examinations. An ideal textbook, therefore, should help him or her on both counts; it should make knowledge easy to acquire and exciting, and also help the student replicate it in an examination. In the course of our medical education, some textbooks will always stand out in our minds. A book that introduces us to a completely new subject and fans the embers of curiosity to explore and learn more, is priceless. The authors have clearly poured their passion into the book and succeeded in bring- ing alive all the intricacies of the subject. For students of Medicine, learning never stops. It is a lifelong process that involves years of dedica- tion to the gathering of knowledge from textbooks, journals, and from clinical experiences. Both the novice student and the practicing clinician can be overwhelmed by the vast amount of information that is currently available. Information is easily assimilated only when it is put together in a concise, simple, and easy-to-read format. Authoring a textbook with an undivided focus on the student and his or her needs is daunting. As authors, the onus is upon us to make sure that the facts presented to the student are evidence based and clinically applicable. To this end, we have researched every piece of information before including it in the text. On the other hand, it is imperative that the book spurs the student to learn more without being intimidated by the subject matter. A student cannot grow to become a good practitioner without a thorough understanding of the pathophysiology of diseases. Skills in diagnostic evaluation and management must follow. We have ensured this pattern in the book so that the subject is presented in a cogent fashion. Clinical guidelines which are tailored to the needs of the population we deal with have been emphasized and included at appropriate places. Each chapter begins with a commonly seen clinical case scenario pertaining to the topic of the chapter and goes on to introduce the topic, explain and illustrate the relevant concepts, and closes with self-assessment. The questions based on the case scenarios are answered at the end of the chapter. Keeping in mind that examinations are a major challenge in a student’s life, the details are pre- sented in Boxes, Tables, Flowcharts, and Figures (line illustrations and clinical images). Figures have simple explanations placed along with the captions. These visuals are of immense help during revi- sion. Besides, the Key Points section at the end of the chapter presents the entire chapter in a nut- shell—this feature too is useful in quick recapitulation of essentials. The Boxes and Tables introduced in the sister volume, Essentials of Gynecology (authored by Prof Lakshmi Seshadri), have been a huge success with students. Naturally, we have retained these features in this book as well. The book is a joint effort by the two of us but with unstinting and generous help and support from our family, colleagues, former and current students, and friends. We are indebted to the editorial team at Wolters Kluwer for their professional inputs. Lakshmi Seshadri Gita Arjun Front Matter.indd 5 19-07-2015 13:00:44 Front Matter.indd 6 19-07-2015 13:00:44  Acknowledgements Essentials of Obstetrics has been a collaborative effort between the two of us. Our greatest inspira- tion and motivation for writing this book has come from the widespread appreciation of Essentials of Gynecology by undergraduate and postgraduate students, teachers, and colleagues and, of course, a request for the companion volume. We would like to place on record our sincere thanks to those who have supported, encouraged, and helped us in several ways. We would like to thank Dr S Suresh and his team at Mediscan Systems, Chennai, for their generous contribution of ultrasonographic images. The colorful clinical photographs are from our former student, Dr Rajnish Samal, Bangalore, and also from the team at Seethapathy Clinic and Hospital, Chennai. Some of the laparoscopic images were provided by Dr Sandip Datta Roy. The cardiotocography traces, partographs, and images were provided by Dr Santosh Benjamin and the postgraduate students of Christian Medical College, Vellore. We gratefully acknowledge their help. Dr Padmini Jasper, Dr Alice George, and other faculty members from the Department of Obstetrics and Gynecology, Christian Medical College Hospital, Vellore, have gone through the chapters and have given their constructive comments for which we are thankful. Our respective husbands, Dr M.S. Seshadri and Dr Arjun Rajagopalan, have been patient and tol- erant of our late working hours, our labile moods, and have managed to survive our ignoring them for long periods of time. They have been our most supportive critics, have read through many of our chapters, and given their expert inputs (at the risk of marital disharmony). The team at Wolters Kluwer: Mrs P Sangeetha, Manager, Commissioning; Dr Vallika Devi Katragadda, Consultant; and Mrs Pooja Chauhan, Manager, Prepress; has worked tirelessly to make this book a possibility and a dream come true. We are indebted to them for their support and contribution. We are thankful to Mr P Saravanan and his team at Digiprezz Media Solutions, for excellent composition and to Mr S Kartikeyan, for beautiful illustrations. Their co-operation and hard work are truly appreciated. Lakshmi Seshadri Gita Arjun Front Matter.indd 7 19-07-2015 13:00:44 Front Matter.indd 8 19-07-2015 13:00:44  Table of Contents Preface v Acknowledgements vii Section 1: Basic Science in Obstetrics 1 1 Anatomy of the Female Reproductive Tract 2 2 Anatomy of the Bony Pelvis and Fetal Skull 24 3 Maternal Physiology in Pregnancy 35 4 Fertilization, Implantation, and Fetal Development 48 5 Placenta, Fetal Membranes, and Amniotic Fluid 61 6 Physiology of Labor 79 7 Clinical Manifestations and Diagnosis of Pregnancy 88 Section 2: Antenatal Management 98 8 History Taking and Examination of the Obstetric Patient 99 9 Preconceptional and Antenatal Care 119 10 Obstetric Ultrasound and Other Imaging 133 11 Antepartum Fetal Surveillance 148 12 Prenatal Screening, Prenatal Diagnosis, and Fetal Therapy 163 13 Medical Termination of Pregnancy 179 Section 3: Intrapartum Management 190 14 Normal Labor: Mechanics, Mechanism, and Stages 191 15 Management of Normal Labor and Delivery 208 16 Induction of Labor 226 17 Intrapartum Fetal Surveillance 238 18 Obstetric Analgesia and Anesthesia 253 19 Operative Vaginal Delivery and Destructive Operations 266 20 Cesarean Section and Management of Pregnancy with Previous Cesarean 282 Section 4: Postpartum Management 300 21 The Normal Puerperium 301 22 The Abnormal Puerperium 308 23 The Newborn 320 24 Common Problems of the Newborn 332 25 Lactation and Breastfeeding 346 26 Contraception: Temporary Methods 355 27 Emergency Contraception and Sterilization 378 Front Matter.indd 9 19-07-2015 13:00:44  Section 5: Obstetric Complications: Antepartum 397 28 Hyperemesis Gravidarum 398 29 Miscarriage and Recurrent Pregnancy Loss 405 30 Ectopic Pregnancy 428 31 Intrauterine Fetal Death 447 32 Multifetal Pregnancy 455 33 Fetal Growth Disorders: Growth Restriction and Macrosomia 474 34 Disorders of Amniotic Fluid 495 35 Preterm Labor and Birth 508 36 Prelabor Rupture of the Membranes 522 37 Postterm Pregnancy 534 38 Red Cell Alloimmunization 542 39 Antepartum Hemorrhage 560 Section 6: Obstetric Complications: Intrapartum 582 40 Abnormal Labor: Abnormalities in Passage and Powers 583 41 Abnormal Labor: Malpositions and Malpresentations 599 42 Abnormal Labor: Breech Presentation and Shoulder Dystocia 621 43 Complications of the Third Stage of Labor 641 44 Obstructed Labor and Uterine Rupture 662 45 Nonhemorrhagic Shock in Pregnancy 670 46 Abnormalities of the Placenta, Umbilical Cord, and Fetal Membranes 683 Section 7: Maternal Diseases Complicating Pregnancy 693 47 Hypertensive Disorders 694 48 Pregestational and Gestational Diabetes 724 49 Hematological Disorders 740 50 Cardiovascular Diseases 758 51 Hepatobiliary and Gastrointestinal Disorders 774 52 Endocrine Disorders and Obesity 790 53 Respiratory, Dermatological, and Connective Tissue Disorders 807 54 Thromboembolic Disorders 815 55 Urinary Tract and Renal Disorders 827 56 Infections 842 57 Benign and Malignant Tumors of the Reproductive Tract 863 Section 8: Social Obstetrics 876 58 Maternal Mortality 877 59 Perinatal Mortality 887 60 National Health Programs in Obstetrics 895 Index 904 Front Matter.indd 10 19-07-2015 13:00:44  Section 1 Basic Science in Obstetrics CH 01_p001-023_v3.indd 1 17-07-2015 10:41:03  Anatomy of 1 the Female Reproductive Tract Case scenario Mrs. AV, 24, primigravida was admitted to labor room at term. Labor was augmented with oxytocin for dysfunctional labor. Second stage of labor was prolonged; therefore, baby was delivered by forceps after pudendal block. There was a fourth degree perineal laceration. Consultant obste- trician was called in to perform an accurate anatomical perineal repair. Introduction Muscles Peritoneum A comprehensive knowledge of the anatomy of the reproductive tract, changes in the anatomy in pregnancy, the anatomy of the bony pelvis, Skin different pelvic configurations, and the anatomy Skin of the anterior abdominal wall stretches of the fetal skull is essential for understanding in pregnancy. There is pigmentation along the the mechanism of labor and managing problems midline forming linea nigra. Stretch marks that that arise during pregnancy and labor. develop in pregnancy are known as striae grav- idarum. The Langer’s lines or dermal fibers are arranged transversely. Anterior abdominal wall Consists of the following layers: Subcutaneous tissue Skin Consists of superficial fatty layer or Camper’s Subcutaneous fascia fascia and deep membranous layer or Scarpa’s Rectus sheath fascia. CH 01_p001-023_v3.indd 2 17-07-2015 10:41:03  Anatomy of the Female Reproductive Tract 3 Rectus sheath abdominis muscles lie on either side of midline. Transverse incisions for cesarean section are Rectus sheath is formed by the aponeurosis of usually extended up to the lateral border of these external and internal oblique and transverse muscles. Pyramidalis is visualized when the abdominis muscles. This sheath covers the rec- anterior rectus sheath is dissected from the mus- tus abdominis muscle. Midway between umbili- cle near the pubic symphysis. These small mus- cus and pubic symphysis is the arcuate line. The cles may be left attached to the rectus sheath. formation of the rectus sheath is different above and below the arcuate line. Above the arcuate line, the internal oblique aponeurosis splits Peritoneum into two layers: the anterior layer fuses with the This is part of the parietal peritoneum that cov- external oblique aponeurosis and the posterior ers the abdominal cavity. layer fuses with transverse abdominis aponeu- rosis to form the anterior and posterior rectus sheath, respectively. Below the arcuate line, the Blood supply aponeuroses of the internal oblique and trans- Blood supply is from branches of femoral and verse abdominis fuse with the external oblique external iliac arteries (Box 1.1). aponeurosis anteriorly to form anterior rectus The superficial epigastric vessels are encoun- sheath (Fig. 1.1). tered during transverse (Pfannenstiel) incision in the subcutaneous tissue. The inferior epigastric Muscles vessels are larger and lie posterior to the rectus muscle. These have to be identified and ligated The muscles of the anterior abdominal wall are: or cauterized. External oblique Internal oblique Box 1.1 Blood supply of the anterior abdominal Transverse abdominis wall Rectus abdominis Branches from femoral artery Pyramidalis Ŧ 5WRGTſEKCNGRKICUVTKE The fibers of the internal oblique and trans- Ŧ 5WRGTſEKCNEKTEWOƀGZKNKCE verse abdominis become aponeurotic more Ŧ External pudendal Branches from the external iliac artery medially than external oblique. Therefore, Ŧ &GGR KPHGTKQT GRKICUVTKE these muscle fibers may have to be cut laterally Ŧ &GGREKTEWOƀGZKNKCE while making a transverse incision. The rectus Skin Anterior rectus Subcutaneous tissue sheath External oblique Rectus muscle Internal oblique Transverse abdominus Posterior rectus Transversalis facia sheath a. Rectus sheath b. Figure 1.1 The rectus sheath. a. Above the arcuate line. The internal oblique aponeurosis splits into two layers. b. Below the arcuate line. The aponeuroses of internal oblique and transverse abdominis fuse with external oblique aponeurosis. CH 01_p001-023_v3.indd 3 17-07-2015 10:41:04  4 Essentials of Obstetrics muscle and may be entrapped or divided if the Clinical implications transverse incision extends too far laterally. Incisions on the abdominal wall for cesarean section may be vertical midline or Pfannenstiel. Vertical incisions CTGCUUQEKCVGFYKVJOQTGRQUVQRGTCVKXGRCKPCPFJKIJGT risk of incisional hernia; hence, transverse incisions are RTGHGTTGF 1VJGT ENKPKECN KORNKECVKQPU CFXCPVCIGU CPF External genitalia (vulva) UWTIKECNCPCVQO[ QHtransverse incisionCTGIKXGPDGNQY #FXCPVCIGU Vulva or the external genitalia consists of ana- Ŧ 2GTHQTOGFCNQPI.CPIGTŏUNKPGU tomical structures listed in Box 1.2 (Fig. 1.2). Ŧ Cosmetically better Ŧ Less pain Mons pubis Ŧ Less risk of hernia 5WTIKECNCPCVQO[ This is the triangular area anterior to the pubic Ŧ Lateral extent of transverse incision bones; it is continuous with the abdominal wall ƒ Up to lateral border of rectus abdominis above and with the labia below. It is filled with Ŧ +PHGTKQTGRKICUVTKEXGUUGNU adipose tissue and covered by hairy skin. ƒ Lie under rectus muscles ƒ Must be clamped/cauterized Ŧ +NKQKPIWKPCN+NKQJ[RQICUVTKEPGTXGſDGTU ƒ May be entrapped/divided in transverse incision Box 1.2 External genitalia (vulva) Mons pubis Labia majora Labia minora Clitoris Nerve supply Vestibule Innervation is by T7–T12 and L1. Abdominal 7TGVJTCNQTKſEG wall at the level of the umbilicus is supplied by 8CIKPCNQTKſEG T10. Ilioinguinal and iliohypogastric nerves (L1) Hymen $CTVJQNKPŏUINCPFU supply the suprapubic area, lower abdomen, 5MGPGŏUINCPFU and mons pubis. These nerve fibers run between Vestibular bulbs the layers of rectus sheath lateral to the rectus Mons pubis Prepuce of clitoris Clitoris Urethral orifice Vestibule Labia majora Labia minora Vaginal orifice Hymen Figure 1.2 Structures in the vulva. CH 01_p001-023_v3.indd 4 17-07-2015 10:41:04  Anatomy of the Female Reproductive Tract 5 Labia majora Hymen These are folds of fatty tissue covered by skin Hymen is the thin membrane that covers the that extend from mons pubis to perineum to vaginal orifice. This ruptures during the first meet in front of the anus, forming the poste- intercourse and remains as small rounded tags. rior fourchette. The skin on the lateral aspect of labia majora is pigmented and covered by hair. Inner aspect is smooth and shiny and contains Bartholin’s glands apocrine, sweat, and sebaceous glands. These are small glands located on the postero- lateral aspect of vaginal orifice, beneath the bulbospongiosus muscle, at 4 o’clock and 8 Labia minora o’clock positions. The glands are about 1 cm in Labia minora are folds of skin that lie medial size and not palpable normally. The ducts are to the labia majora, encircling the urethral and 2 cm long and open into the vaginal orifice, vaginal orifices. Posteriorly they fuse with the superficial to the hymen. The glands are com- posterior fourchette but anteriorly they divide pound racemose and lined by cuboidal epithe- to form a hood or prepuce and a frenulum for lium. Ducts are lined by cuboidal epithelium the clitoris. proximally and transitional epithelium distally. The secretions provide lubrication during sex- ual intercourse. Clitoris Clitoris is the homologue of the penis in men Skene’s glands and is formed by two corpora cavernosa and erectile tissue. It is about 1.5–2 cm in length and These are paraurethral glands that are homol- is located anterior to the urethral orifice between ogous of the prostate and are located on either the anterior folds of labia minora. side of the distal urethra. The ducts open into the urethra, close to the external meatus. Vestibule The area between the labia minora is referred to Vestibular bulbs as the vestibule. This is perforated by the urethral These are elongated masses of erectile tissue and vaginal orifices. located beneath the bulbospongiosus muscle on The urethral orifice (meatus) is a vertical either side of the vaginal orifice. They meet ante- opening above the vaginal orifice. The ducts of riorly as a narrow strip. Skene’s (paraurethral) glands open just inside or outside the meatus. Changes in pregnancy Vulva becomes soft in pregnancy and varicosi- 7TGVJTCNQTKſEG ties may develop. Vulval edema may develop in This is otherwise known as external urethral severe preeclampsia. meatus and is located in the anterior part of the vestibule. Clinical implications Clinical implications of changes in vulva during preg- 8CIKPCNQTKſEG nancyCTGIKXGPDGNQY This lies between the labia minora and is par- Varicose veins of the vulva tially covered by a thin membrane called hymen. Ŧ $NGGFKPIFWTKPIFGNKXGT[ Vulval edema The ducts of the Bartholin’s glands open into the Ŧ &KHſEWNV[KPGRKUKQVQO[ vaginal orifice laterally between the hymen and Ŧ +ORCKTGFJGCNKPI labia minora. CH 01_p001-023_v3.indd 5 17-07-2015 10:41:04  6 Essentials of Obstetrics Pubic symphysis Pubic symphysis ubpubic angle schiopubic rami Ischial Urogenital triangle tuberosity uperficial trans erse perinei muscle schial tuberosity Coccyx acrotuberous ligament Coccy Figure 1.3 The anatomical perineum. This is a diamond- Figure 1.4 6JGWTQIGPKVCNVTKCPING6JGDQWPFCTKGUCTG shaped area that extends from the pubis anteriorly to UWDRWDKECPINGCPVGTKQTN[UWRGTſEKCNVTCPUXGTUGRGTKPGK the coccyx posteriorly and the ischial tuberosities muscle posteriorly; ischiopubic rami and the ischial laterally. tuberosities laterally. The perineum Box 1.4 Muscles of the perineum 5WRGTſEKCNRGTKPGCNOWUENGU The anatomical or true perineum is a diamond- Ŧ Ischiocavernosus shaped area that extends from pubis anteriorly Ŧ $WNDQURQPIKQUWU to coccyx posteriorly and the ischial tuberosities Ŧ 5WRGTſEKCNVTCPUXGTUGRGTKPGK laterally (Fig. 1.3). This is divided by an imagi- Deep perineal muscles nary line between the two ischial tuberosities into Ŧ Deep transverse perinei anterior or urogenital triangle and posterior or Ŧ Urethral sphincter anal triangle. The urogenital triangle Muscles of the perineum The urogenital triangle forms the anterior trian- They fall into two groups—superficial and gle of the perineum. deep—as demarcated by the perineal membrane (Box 1.4; Fig. 1.5). Boundaries 5WRGTſEKCNRGTKPGCNOWUENGU Anterior: Subpubic angle Posterior: Superficial transverse perinei muscles The ischiocavernosus muscles run along the Lateral: Ischiopubic rami and ischial tuberosi- ischiopubicrami, originate at the ischial tuber- ties (Fig. 1.4) osity and are inserted into the ischiopubis. The bulbospongiosus muscles are medial and lie over the vestibular bulbs. They originate at the Contents perineal body and are inserted into the clitoris. The contents of the urogenital triangle are listed The superficial transverse perinei muscles are in Box 1.3. attached to the ischial tuberosities laterally and perineal body medially (Box 1.5). Box 1.3 Contents of the urogenital triangle Deep perineal muscles Vulva and its contents The urethral sphincter consists of a sheet of mus- 7TQIGPKVCNFKCRJTCIO cle that arises from the ischiopubis and is inserted 5WRGTſEKCNRGTKPGCNOWUENGU into the urethra and vagina. This muscle functions Deep perineal muscles along with deep transverse perinei, pubourethra- Blood vessels, nerves, and lymphatics lis fibers of the levator ani, and bulbospongiosus CH 01_p001-023_v3.indd 6 17-07-2015 10:41:04  Anatomy of the Female Reproductive Tract 7 Ischiocavernosus Bulbospongiosus Perineal body Pubovaginalis Urogenital diaphragm Transversus perinei superficialis Iliococcygeus Sphincter ani externus Coccygeus Coccyx Figure 1.5 /WUENGUQHRGTKPGWO5WRGTſEKCNOWUENGUQHVJGRGTKPGWOCTGUGGP Box 1.5 5WRGTſEKCNCPFFGGRRGTKPGCNOWUENGU The anal triangle Muscle Origin Insertion Boundaries Ischiocavernosus Ischial Ischiopubis tuberosity Anterior: Superficial transverse perineal muscles Posterior: Coccyx $WNDQURQPIKQUWU 2GTKPGCNDQF[ %NKVQTKU Lateral: Ischial tuberosities and sacrotuberous 5WRGTſEKCN +UEJKCN 2GTKPGCN ligaments (Fig. 1.6) transverse perinei tuberosity body Urethral sphincter Ischiopubis Urethra and XCIKPC Contents Deep transverse Ischium Lateral Contents of anal triangle are listed in Box 1.6. RGTKPGK XCIKPCNYCNN Anal canal Anal canal extends from the anorectal junction muscles to aid the bladder muscles in closing the to the anal verge and is approximately 4 cm in urethra. The deep transverse perinei muscles are length. The dentate line is located 2 cm from the located above the perineal membrane, arise from anal verge. The canal is lined by columnar epi- the ischial bone, and are inserted into the lateral thelium above the dentate line and squamous vaginal wall. epithelium below the dentate line. The anal sphincters Perineal membrane There are two anal sphincters—external and inter- Perineal membrane is a dense triangular conden- nal. The external anal sphincter is made of skeletal sation of fascia that stretches between the two ischiopubic rami and is pierced by the urethra and Box 1.6 Contents of anal triangle vagina. This membrane separates the superficial from the deep compartment of the perineum. The Lower end of anal canal perineal membrane and the deep transverse per- Anal sphincters #PQEQEE[IGCNDQF[ TCRJG inei muscles attach the lower vagina and urethra Ischiorectal fossae to pubic rami and provide support to these Blood vessels, lymphatics, and nerves structures. CH 01_p001-023_v3.indd 7 17-07-2015 10:41:04  8 Essentials of Obstetrics uper icial tra s erse peri ei muscles al tria le Ischial tuberosity al sphi cters acrotuberous li ame t al ca al ococcy eal raphe Coccyx Figure 1.6 6JGCPCNVTKCPING6JGDQWPFCTKGUCTGUWRGTſEKCNVTCPUXGTUGRGTPGKOWUENGUCPVGTKQTN[EQEE[ZRQUVGTKQTN[ KUEJKCNVWDGTQUKVKGUCPFUCETQVWDGTQWUNKICOGPVUNCVGTCNN[ muscle and has three parts—subcutaneous, Box 1.7 Boundaries and contents of superficial, and deep. The fibers of external anal ischiorectal fossa sphincters merge with each other and are attached to perineal body anteriorly and to puborectalis Boundaries Ŧ Base: Perineal skin and anococcygeal body posteriorly. Ŧ Apex: Point where obturator and anal fascia meet Anococcygeal body is a fibromuscular struc- Ŧ Lateral: Ischial tuberosity, obturator internus muscle, ture located between the anus and coccyx. The obturator fascia fibers of the levator ani and anal sphincters are Ŧ Medial: Sphincter ani internus, levator ani attached to it. Ŧ 2QUVGTKQT)NWVGWUOCZKOWUUCETQVWDGTQWUNKICOGPV Contents Ischiorectal fossae Ŧ Ischiorectal pad of fat Ŧ Inferior rectal nerve and vessels These lie on either side of the anal canal. They Ŧ Pudendal canal and its contents are wedge-shaped, fat-filled spaces. Boundaries Ŧ Posterior labial nerve, perineal branch of fourth and contents of the fossae are given in Box 1.7 sacral nerve, cutaneous branch of S2, S3 and Fig. 1.7. Perineal body 2GNXKEƀQQT Perineal body is a fibromuscular structure that The pelvic organs are supported in the upright forms the center point of the perineum and is sit- position by a fibromuscular floor that includes uated between the anus and lower vagina. Several the pelvic diaphragm, muscles of the deep peri- muscles are inserted into it (Box 1.8; Fig. 1.8). neal compartment, and the perineal membrane. ectum an Le ator ani anal canal bturator muscle schium Pu en al bturator fascia essels an ner e at nal sphincter Figure 1.7 %QTQPCNUGEVKQPQHVJGKUEJKQTGEVCNHQUUCG6JGUGCTGYGFIGUJCRGFURCEGUQPGKVJGTUKFGQHVJGCPCNECPCN CH 01_p001-023_v3.indd 8 17-07-2015 10:41:05  Anatomy of the Female Reproductive Tract 9 ulbospongiosus Pubo aginalis eep trans erse perinei Perineal bo y uperficial trans erse perinei phincter ani e ternus Puborectalis Coccygeus Figure 1.8 Muscles that form perineal body. Box 1.8 Muscles inserted into perineal body Box 1.9 Components of levator ani Sphincter aniexternus 2WDQEQEE[IGWU $WNDQURQPIKQUWU Ŧ Puborectalis 5WRGTſEKCNVTCPUXGTUGRGTKPGK Ŧ 2WDQXCIKPCNKU Deep transverse perinei +NKQEQEE[IGWU Levator ani Ŧ 2WDQXCIKPCNKU Ŧ Puborectalis The muscle fibers of the levator ani mus- cles arise from the arcus tendineus or white line which is a thickening of the fascial covering of Clinical implications the obturator internus muscle and extends from 2GTKPGCN DQF[ UVTGVEJGU FWTKPI FGNKXGT[ CPF VJG OWU- the pubic bone to ischial spine (Fig. 1.10). The ENGUCTGKPXQNXGFKPRGTKPGCNVGCTU&COCIGVQRGTKPGCN fibers of levator ani pass backwards and medi- DQF[ECWUGUCFGſEKGPVRGTKPGWOICRKPIQHVJGKPVTQK- tus with resultant sexual problems, and loss of support ally to be inserted into perineal body, rectal wall, HQT NQYGT QPGVJKTF QH XCIKPC 6JKTF CPF HQWTVJ FGITGG anococcygeal raphe, and coccyx. In addition, the VGCTUNGCFVQCPCNKPEQPVKPGPEG5WTIKECNKPEKUKQPQPVJG medial and anterior fibers that arise from the RGTKPGWOVQGPNCTIGVJGKPVTQKVWUVQHCEKNKVCVGFGNKXGT[KU pubis (pubovaginalis) cross the lateral vaginal known as episiotomy (see Chapter 15, Management of wall between the middle and lower third and normal labor and delivery). are inserted into the vaginal wall and perineal body. Some fibers decussate behind the urethra as well. They form a sling around the urethra, Pelvic diaphragm vagina, and rectum, pulling these structures Pelvic diaphragm consists of levator ani mus- anteriorly toward the pubis. When the muscle cle covered by pelvic fascia. The muscle covers contracts, the urethra, vagina, and rectum are the space from the pubic bone to coccyx and kinked and narrowed. The uterus and vagina from one pelvic side wall to another forming lie horizontally on the pelvic floor. The contrac- a funnel-shaped support. The muscle has two tion of the levator ani also maintains the vagina components (Box 1.9; Fig. 1.9). The coccygeus, in its horizontal position at rest. formerly called ischiococcygeus, extends from The coccygeus, also called ischiococcygeus, the ischial spine to coccyx but is not a part of though not part of the levator ani, also forms levator ani. the posterior part of the pelvic floor and pelvic CH 01_p001-023_v3.indd 9 17-07-2015 10:41:05  10 Essentials of Obstetrics Urethra Pubic bone Pubo aginalis Vagina rcus ten ineus fascia pel is nal canal schial tuberosity Puborectalis leococcygeus Coccygeus Coccy Figure 1.9 %QORQPGPVUQHNGXCVQTCPKOWUENGōRWDQTGEVCNKURWDQXCIKPCNKUCPFKNKQEQEE[IGWU Box 1.10 Internal genital organs 8CIKPC Uterus Fallopian tubes Ovary bturator ascia a obturator i ter us muscle Pubis Internal genital organs rcus te i eus The internal genital organs are listed in Box 1.10 e ator a i and elaborated in the following text. a i a Vagina Figure 1.10 Arcus tendineus fascia pelvis. It extends from the pubic bone to the ischial spine. Vagina is the fibromuscular tube that extends from vestibule to uterine cervix (Box 1.11). The attachment of vagina to the cervix is at its Clinical implications middle (Fig. 1.11). Therefore, a gutter is formed The location, attachments, and functions of the levator all around the cervix, between it and the vagina, ani muscle have several clinical implications. 6JGNGXCVQTCPKOWUENGJCUCTGUVKPIVQPGVJCVMGGRUVJG RGNXKEƀQQTENQUGFCPFRTGXGPVUJGTPKCVKQPQHVJGWVGTWU Box 1.11 Vagina and cervix. Fibromuscular tube from vestibule to cervix The shape of the levator ani muscle and the direction Axis horizontal QHVJGſDGTURNC[COCLQTTQNGKPKPVGTPCNTQVCVKQPQHVJG Closely applied RTGUGPVKPIRCTVKPNCDQT Ŧ Anteriorly Puborectalis contributes to anal continence. ƒ Bladder +PLWT[VQNGXCVQTCPKOWUENGFGVGEVGFD[WNVTCUQPQITC- RJ[ CPF OCIPGVKE TGUQPCPEG KOCIKPI QEEWTU FWTKPI ƒ Urethra XCIKPCNFGNKXGT[CPFECWUGURGNXKEQTICPRTQNCRUG Ŧ Posteriorly ƒ Posterior cul-de-sac ƒ Rectum ƒ Anal canal support. It originates from the ischial spine and ƒ Perineal body sacrospinous ligament and is inserted into the Anterior and posterior walls in apposition lateral part of the lower sacrum and coccyx. CH 01_p001-023_v3.indd 10 17-07-2015 10:41:06  Anatomy of the Female Reproductive Tract 11 Uterus Box 1.12 Structure of vagina la er Mucosa Ŧ 5VTCVKſGFUSWCOQWUGRKVJGNKWO Subepithelial connective tissue Pouch of Muscle layer nterior forni ouglas Ŧ 1WVGTNQPIKVWFKPCN Pubic bone Ŧ Inner circular ectum Urethra Condensed endopelvic fascia Posterior forni Vagina a. Perineal bo y Clinical implications Clinical implications of changes in vagina during preg- nancyCTGIKXGPDGNQY Bluish discoloration of vulva Ŧ &KCIPQUKUQHRTGIPCPE[.QYGTKPIQHXCIKPCNR* Ŧ 2TQVGEVKQPCICKPUVXCIKPCNKPHGEVKQPU Uterine artery Lateral Ureter forni Uterus Vagina Uterus is a pear-shaped hollow viscus located b. between the bladder and rectum. It is divided into cervix and uterine corpus, the dividing line Figure 1.11 a.5CIKVVCNUGEVKQPQHVJGXCIKPCUJQYKPIVJG being the internal os. CZKUQHVJGXCIKPCVJGCPVGTKQTCPFRQUVGTKQTHQTPKEGUCPF its relationship to bladder and urethra. b. Coronal section of VJGXCIKPCUJQYKPIVJGNCVGTCNHQTPKEGUCPFVJGKTRTQZKOKV[ Cervix to ureters. The attachment of the vagina divides the cervix into upper supravaginal cervix and lower por- tio vaginalis (Fig. 1.12). It has an external os and called fornices. Ureter and uterine artery are in internal os, and a cervical canal in between. Total close proximity to lateral fornices. The posterior length of cervix is 2.5–3 cm. The external os is cir- attachment is at a higher level making the poste- cular in the nullipara but becomes a transverse rior fornix deep. The anterior wall of the vagina slit after childbirth. Anatomical features of cervix is, therefore, shorter than the posterior wall. are given in Box 1.13. The opening at the vestibule is partially covered by hymen. The vaginal walls have rugae which allow stretching during parturition. The axis of the vagina is horizontal. Box 1.13 Anatomical features of the cervix Cervix divided into ƒ UWRTCXCIKPCNEGTXKZ Structure of vagina ƒ RQTVKQXCIKPCNKU Vaginal wall is composed of three layers (Box 1.12). Consists of Ŧ external os Ŧ internal os Changes in vagina during pregnancy Ŧ endocervical canal between the two There is increased vascularity and bluish discol- Structure includes oration of the vagina, described as Chadwick’s Ŧ ſDTQOWUEWNCTYCNN Ŧ endocervical canal—columnar epithelium sign. Increase in glycogen-containing cells results Ŧ GEVQEGTXKZōUVTCVKſGFUSWCOQWUGRKVJGNKWO in lowering of pH due to increase in lactic acid. Ŧ INCPFUōUGETGVGOWEWU This offers protection from infection. CH 01_p001-023_v3.indd 11 17-07-2015 10:41:06  12 Essentials of Obstetrics un us cm Corpus upra aginal cer i Cer i cm Portio aginalis cer i Vagina Figure 1.12 Uterus and cervix. Uterine fundus is the part above the line of attachment of the fallopian tubes. The part of VJGEGTXKZCDQXGVJGCVVCEJOGPVQHVJGXCIKPCKUUWRTCXCIKPCNEGTXKZCPFDGNQYVJKUKURQTVKQXCIKPCNKUEGTXKZ Changes in cervix during pregnancy mechanism, and stages). During labor, cervix Cervix undergoes changes in pregnancy. In the undergoes effacement and dilatation to allow first trimester of pregnancy, the lower part of the passage of fetus. the uterus softens, while the fundus and cervix Early effacement and dilatation occurs in are firmer. This softening of the lower segment is some women, leading to recurrent pregnancy described as Hegar’s sign (see Chapter 7, Clinical loss or preterm labor. manifestations and diagnosis of pregnancy). The cervix remains closed in pregnancy till onset of Uterine corpus labor. Endocervical epithelium proliferates and The size and shape of the uterus changes with gives rise to ectropion. There is also plenty of changes in hormone levels associated with mucus production and a mucous plug forms in puberty and pregnancy. The dimensions of nul- the cervical canal, which is expelled at the onset liparous uterus are given in Box 1.14. The uterus of labor along with bloody discharge known as is normally anteverted and anteflexed. Flexion is show (see Chapter 14, Normal labor: Mechanics, the angle between the uterus and cervix and ver- sion is the angle between the uterus and vagina. Clinical implications Clinical implications of changes in cervix during preg- nancyCTGIKXGPDGNQY Box 1.14 Uterus *GICTŏUUKIP Pear shaped Ŧ &KCIPQUKUQHRTGIPCPE[.GPIVJEO /WEQWURNWI Anteroposterior thickness: 2.5 cm Ŧ 2TQVGEVUCICKPUVCUEGPFKPIKPHGEVKQP.GPIVJQHECXKV[EO Show Body: Cervix ratio Ŧ 5KIPQHſTUVUVCIGQHNCDQT Ŧ At birth: 1:1 Effacement and dilatation Ŧ Adult: 2:1 Ŧ Normal labor Corpus is divided into Dilatation before term Ŧ Isthmus: Just above the internal os Ŧ Preterm labor Ŧ Cornu: At insertion of fallopian tube Ŧ 2TGIPCPE[NQUU Ŧ Fundus: Above the level of cornu CH 01_p001-023_v3.indd 12 17-07-2015 10:41:06  Anatomy of the Female Reproductive Tract 13 Structure of uterus Box 1.15 Histology of uterus The uterine wall consists of three layers—inner Endometrium endometrium, outer serosa, and a middle layer Ŧ Columnar epithelium composed of smooth muscles called myome- Ŧ Cellular stroma trium. The endometrial cavity is continuous with Ŧ Glands that of the tubes, cervix, and vagina. The endome- Ŧ Specialized stroma trium, including glands and stroma, is very sensi- Myometrium tive to estrogen and progesterone and undergoes Ŧ Inner circular Ŧ /KFFNGKPVGTNCEKPI changes during menstrual cycle and pregnancy. Ŧ 1WVGTNQPIKVWFKPCN The myometrium consists of three layers. Serosa (peritoneum) These layers are more distinct during pregnancy. Ŧ Incomplete anteriorly Outer longitudinal Ŧ Complete posteriorly Middle interlacing, crisscross Inner circular Changes in uterus during pregnancy The outer longitudinal fibers of myometrium are continuous with those of the tubes. The mid- Major anatomical changes take place in the dle layer of interlacing fibers is important for uterus during pregnancy. uterine contraction and retraction. The blood vessels pass through this layer and the contrac- a. Changes in size and shape tion of the fibers in this layer occludes the ves- In the prepregnant state, uterus is a pear-shaped sels, forming living ligatures and stopping the organ, which weighs about 100 g, measures 10 × bleeding after parturition. The inner circular 5 × 2.5 cm, and has a cavity of about 10 mL. Rapid layer is thin and insignificant (Fig. 1.13). growth in pregnancy is due to hyperplasia and The serosa or peritoneum covering the uterus hypertrophy. By term, uterus weighs 1000 g and stops at the uterovesical junction anteriorly but has a capacity to hold 5 L or more. Shape of the extends down to form the cul-de-sac or pouch of uterus changes with advancing pregnancy from Douglas posteriorly (Box 1.15). The cul-de-sac is pear shaped to spherical at 20 weeks and elon- the most dependent part of the pelvis, and there- gates toward term, becoming longitudinally oval fore, fluids, pus, and blood collect here to form (Box 1.16). abscess or hematocele. This can be easily accessed through the posterior fornix. b. Formation of lower segment The lower segment develops from the isthmus and is about 10 cm in length by term. The differ- ence between the two segments becomes more obvious as pregnancy advances. The junction between the two segments is at the level of the pubic symphysis and is marked by the level at uter longitu enal Mi le crisscross Box 1.16 Changes in the uterus during loo essels pregnancy nner circular Size Increase in uterine size Ŧ More at the fundus Ŧ Due to hypertrophy and hyperplasia Shape Figure 1.13 &KCITCOOCVKETGRTGUGPVCVKQPQHVJGOWUENG Ŧ Spherical by 12 weeks layers of the uterine myometrium. The myometrium Ŧ.QPIKVWFKPCNN[QXCND[VGTO EQPUKUVUQHQWVGTNQPIKVWFKPCNKPPGTEKTEWNCTCPFOKFFNG Volume KPVGTNCEKPIETKUUETQUUſDGTU6JGDNQQFXGUUGNURCUU Ŧ Increases to 5 L or more VJTQWIJVJGOKFFNGNC[GT CH 01_p001-023_v3.indd 13 17-07-2015 10:41:06  14 Essentials of Obstetrics which the peritoneum becomes loosely adher- Box 1.17 Fallopian tubes ent to the anterior uterine wall..GPIVJ#DQWVEO E%JCPIGUKPDNQQFƀQY (QWTTGIKQPU Ŧ Interstitial: Narrowest, within the uterine cornu Blood flow to the uterus and cervix increases Ŧ Isthmus: Narrow, close to uterine cornu steadily to 500 mL/min, which is five times more Ŧ Ampullary: Broader, thin walled, lateral to isthmus than the nonpregnant state. Uterine vessels Ŧ +PHWPFKDWNWO(WPPGNUJCRGFGPFUKPſODTKCG enlarge gradually and become tortuous. Functions Ŧ Ovum pickup d. Changes in myometrium Ŧ Site of fertilization The three layers become distinct and the middle Ŧ Transport of fertilized ovum layer becomes prominent. nfun ibular e. Uterine activity nterstitial sthmus Spontaneous contractions called Braxton Hick’s contractions begin at about 20 weeks and con- mpullary tinue till term. This uterine activity facilitates the development of lower segment and softens the cervix. imbriae Fallopian tubes Figure 1.14 The fallopian tube. The tube is narrow at the isthmus and broad at the ampullary part. The tubes are about 10 cm in length and extend laterally from the cornual ends of the uterus into the peritoneal cavity. Each tube is Box 1.18 Structure of the fallopian tube divided into four regions (Box 1.17; Fig. 1.14). Mucosa The infundibulum has fimbriae with cilia to Ŧ Ciliated columnar epithelium aid in ovum pickup. Fertilization takes place Muscularis in the tube, and the blastocyst is transported Ŧ 1WVGTNQPIKVWFKPCN to the uterine cavity where implantation takes Ŧ Inner circular place. Outer Ŧ Serosa The structure of the tube is given in Box 1.18. The tube has three layers—inner mucosa, outer serosa, and muscularis layer between the two. Clinical implications When implantation of fertilized ovum takes place in the HCNNQRKCPVWDGGEVQRKERTGIPCPE[TGUWNVU+VECPTWRVWTG Clinical implications NGCFKPI VQ JGOQRGTKVQPGWO UJQEM CPF RGNXKE JGOC- Clinical implications of changes in uterine anatomy tocele. during pregnancyCTGIKXGPDGNQY %JCPIGUKPUK\GUJCRGRQUKVKQP Ŧ #EEQOOQFCVGUITQYKPIHGVWU Ovaries %JCPIGUKPO[QOGVTKWO Ŧ Uterine contraction in labor The tube and ovary together are referred to as Ŧ 4GVTCEVKQPCPFJGOQUVCUKUKPVJKTFUVCIG adnexa. The ovaries are the female gonads. The (QTOCVKQPQHNQYGTUGIOGPV size of the ovaries varies with age, sex, steroid Ŧ Facilitates labor hormone levels, and certain medications. The 6JKPPKPIQHNQYGTUGIOGPV ovaries are located on either side of the uterus, Ŧ Predisposes to rupture uterus close to the infundibulum of the tubes. They are (QTOCVKQPQHTGVTCEVKQPTKPI connected to the uterine cornu by the ovarian lig- Ŧ Indicates obstructed labor aments and to the broad ligament by mesovarium CH 01_p001-023_v3.indd 14 17-07-2015 10:41:07  Anatomy of the Female Reproductive Tract 15 arian Hilum Meso arium Box 1.20 Structure of the ovary ligament Mesosalpin Cortex Ŧ Cuboidal surface epithelium Ŧ Specialized stroma Ŧ Follicles Medulla Ŧ Fibromuscular tissue Ŧ Blood vessels Ligaments of the uterus and cervix The endopelvic fascia condenses in some areas nfun ibulopel ic to form ligaments that support the uterus and ligament other pelvic structures (Box 1.21; Fig. 1.16). Figure 1.15 Attachments of the ovary. Infundibulopelvic NKICOGPVCVVCEJGUVJGQXCT[VQVJGNCVGTCNRGNXKEYCNNCPF Cardinal or Mackenrodt’s ligaments QXCTKCPNKICOGPVVQVJGQXCT[/GUQXCTKWONKGUDGVYGGP VJGQXCT[CPFVJGDTQCFNKICOGPV These extend from the lower part of the uterus, supravaginal cervix and lateral vaginal fornix to the lateral pelvic wall. The loose cellular tissue Box 1.19 Ovaries in this area is referred to as parametrium. The Size Ŧ 3 x 2 cm Connected by Box 1.21 Ligaments of the uterus and cervix Ŧ mesovarium (mesentery) to posterior surface of DTQCFNKICOGPV %CTFKPCNNKICOGPVU Ŧ QXCTKCPNKICOGPVVQWVGTKPGEQTPW 2WDQEGTXKECNNKICOGPVU Ŧ KPHWPFKDWNQRGNXKENKICOGPVVQNCVGTCNRGNXKEYCNN 7VGTQUCETCNNKICOGPVU 4QWPFNKICOGPVU $TQCFNKICOGPVU (Fig. 1.15). The ovarian vessels are carried in a 1XCTKCPNKICOGPVU +PHWPFKDWNQRGNXKENKICOGPVU fold of peritoneum, called the infundibulopelvic ligaments, from the lateral pelvic wall to the ovary (Box 1.19). Pubocer ical li ame t Structure la er urethra The ovary is divided into an outer cortex and inner medulla (Box 1.20). The cortex contains a i a the specialized stroma and the follicles and is responsible for the important functions of ovu- lation and steroid hormone production. Car i al li ame t ectum Changes in ovaries during pregnancy terosacral li ame t Ovaries enlarge and become vascular. The cor- acrum pus luteum continues to grow and secrete hor- mones till 7–8 weeks and begins to degenerate at Figure 1.16.KICOGPVUCVVCEJGFVQVJGNQYGTWVGTWUCPF 12 weeks when placenta takes over. EGTXKZōECTFKPCNWVGTQUCETCNCPFRWDQEGTXKECNNKICOGPVU CH 01_p001-023_v3.indd 15 17-07-2015 10:41:07  16 Essentials of Obstetrics ureter, before entering the bladder, traverses this Infundibulopelvic ligaments ligament and is encased in a fascial sheath called ureteric tunnel which lies 2 cm lateral to the cer- These are lateral extensions of the broad liga- vix. The uterine artery crosses to the uterus above ments between the ovary and pelvic wall. They the ureter at this point. The descending cervical contain the ovarian vessels. branch of the uterine artery courses through this ligament. Pelvic ureters Pubocervical ligaments The ureters are located retroperitoneally and run from the renal pelvis to urinary bladder. The This condensation of the pubovesicocervical fascia abdominal segments lie on the psoas muscle passes from the anterolateral aspect of the cervix and run downwards and medially. They enter the to the posterior surface of pubic bone. Some fibers pelvis by crossing the common iliac vessels from extend from the bladder and the pubis and form lateral to medial aspect at their bifurcation just the bladder pillars. Pubocervical ligaments merge medial to the ovarian vessels (Fig. 1.17a and b). posterolaterally with the cardinal ligaments. They can be found attached to the medial leaf of the posterior peritoneum during dissection. Uterosacral ligaments At the level of the ischial spines, they turn for- ward and medially toward the base of the broad These ligaments extend from the posterior ligament. They then enter the ureteric canal in part of the supravaginal cervix to the sacrum. the cardinal ligament, crossing under the uterine They lie on either side of the rectosigmoid. vessels. Here they are 2 cm lateral to the cervix. Anterolaterally they merge with cardinal lig- The ureters run medially and enter the bladder aments. Frankenhauser’s plexus of nerves are close to the anterior vaginal wall (Box 1. 22). located mainly along these ligaments. Round ligaments Box 1.22 The course of the pelvic ureters These are vestiges of the gubernaculums and are Cross the common iliac at bifurcation made of fibromuscular tissue. They extend lat- Lie attached to the posterior peritoneum erally from the uterine cornu extraperitoneally, 4GCEJVJGNGXGNQHWVGTQUCETCNNKICOGPVU enter the inguinal canal, and finally merge with Turn forward at ischial spine the skin and connective tissue of the mons pubis 'PVGTVJGDCUGQHDTQCFNKICOGPVU and labia majora. Cross under the uterine vessels 'PVGTWTGVGTKEECPCNKPECTFKPCNNKICOGPVU Run forward to enter the bladder Broad ligaments.KGENQUGVQCPVGTKQTXCIKPCNYCNN The peritoneum on the anterior and poste- rior surface of the uterus spreads out laterally toward the pelvic wall to form the broad liga- Clinical implications ments. Between the two layers of peritoneum is Due to the close proximity to other structures in the pel- the pelvic cellular tissue containing ureter and XKUVJGWTGVGTKURTQPGVQKPLWT[FWTKPIXCTKQWUUWTIKECN the plexus formed by the anastomosis of uterine procedures. Points at which ureter is prone to injury are and ovarian vessels. The round ligaments, tubes, listed below. and ovarian ligaments are covered by the perito- Site Procedure neum of the broad ligament and are contained 2GNXKEDTKO %NCORKPIQHKPHWPFKDWNQRGNXKE in its upper part.  NKICOGPVU $KHWTECVKQPQH +PVGTPCNKNKCECTVGT[NKICVKQP common iliac Ovarian ligaments $TQCFNKICOGPV 7VGTKPGCTVGT[NKICVKQP They pass from the medial pole of the ovaries to %CTFKPCNNKICOGPV &KUUGEVKQPQHWTGVGTKEVWPPGN  %NCORKPIQHECTFKPCNNKICOGPV the uterine cornu posterior to the attachment of 7RRGTXCIKPC %NCORKPIQHXCIKPCNCPING the tubes. CH 01_p001-023_v3.indd 16 17-07-2015 10:41:07  Anatomy of the Female Reproductive Tract 17 la er bturator artery teri e artery reter uperior esical artery a i a reter aria artery i u ibulopel ic li ame t ectum a. arian Ureter Common iliac artery artery acrum ifurcation ternal iliac Uterus nternal iliac ary Urinary bla er Uterine artery b. Pubic bone Figure 1.17 The pelvic ureters. a. The course of the ureters. b. The relationship of the pelvic ureters. The Ureters enter VJGRGNXKUD[ETQUUKPIVJGEQOOQPKNKCECTVGT[CVKVUDKHWTECVKQPVWTPHQTYCTFVQGPVGTVJGWTGVGTKEECPCNETQUUKPIWPFGTVJG uterine vessels. The ureters receive rich blood supply from Urinary bladder and urethra all the blood vessels in the pelvis. These vessels anastomose to form a plexus on the adventitia of The urinary bladder and urethra are in close the ureters before entering it. Therefore, the ure- proximity to the anterior surface of uterus and ter is protected from devascularization unless it vagina. The proximity and susceptibility to injury is skeletonized. varies with the amount of urine in the bladder. CH 01_p001-023_v3.indd 17 17-07-2015 10:41:08  18 Essentials of Obstetrics into external and internal iliacs at the sacroiliac Clinical implications joints. The ureters cross the common iliacs at Since the urinary bladder lies just anterior to lower uter- their bifurcation. KPGUGIOGPVKPLWTKGUVQVJGDNCFFGTCTGEQOOQPFWTKPI UWTIGT[ 6JG DNCFFGT QT WTGVJTC OC[ DG EQORTGUUGF The internal iliac (hypogastric) artery lies pos- between the fetal head and pubic bone in obstructed teromedial to the external iliac vessels. The ureter NCDQTNGCFKPIVQRTGUUWTGPGETQUKUCPFWTKPCT[ſUVWNCG is anterior and the internal iliac vein is posterior Obstetric injuries of the urinary bladder to the artery. The artery on each side divides into Rupture uterus anterior and posterior divisions. The posterior Cesarean section division exits the pelvis and does not give off any Ŧ 9JKNGGPVGTKPIRGTKVQPGWO visceral branches. The anterior division gives rise Ŧ 9JKNGKPEKUKPIWVGTQXGUKECNRGTKVQPGWO to several branches which supply the internal Ŧ 9JKNGRWUJKPIDNCFFGTFQYP and external genitalia (Box 1.23; Fig. 1.18). Ŧ Downward extension of uterine incision The obturator and superior vesical are the 8CIKPCNFGNKXGT[ first two branches of the anterior division, fol- Ŧ Rotational forceps lowed by the uterine artery. The vaginal artery Ŧ Destructive operations may arise from the uterine artery. After giving Obstructed labor off these branches in the pelvis, the internal iliac Ŧ 2TGUUWTGPGETQUKUCPFſUVWNC artery continues as internal pudendal artery which hooks behind the ischial spines to enter The superior surface of bladder is adjacent to the pudendal canal in the ischiorectal fossa. Here the anterior uterine surface. Base of the bladder it gives off two more branches—the inferior rec- is located adjacent to the anterior vaginal wall. tal and perineal arteries. The vessel then ends as Bladder neck and urethra lie anterior to the ante- dorsal artery of the clitoris. The parietal branches rior vaginal wall. The space between the bladder supply the respective muscles and tissues. and pubic symphysis is called space of Retzius. Uterine arteries Blood supply The uterine arteries run medially and cross over the ureter about 2 cm lateral to the internal os in The internal and external genitalia have a rich the broad ligament. At the lateral border of the blood supply in order to allow for the needs of uterus, they turn sharply upward and run along pregnancy and labor. the side of the uterus as arcuate artery (Fig. 1.19). Before turning upward, they give off the descend- The ovarian vessels ing cervical branches. The descending branch The ovaries are supplied by ovarian vessels. The ovarian arteries arise from the aorta just below Box 1.23 Branches of the anterior division of the renal vessels. They descend retroperitoneally, internal iliac artery cross the ureter anteriorly, and enter the infun- dibulopelvic ligaments. After supplying the ovary, Parietal branches Ŧ Obturator they give off branches to supply the fallopian Ŧ +PHGTKQTINWVGCN tube and finally anastomose with the ascending Ŧ Internal pudendal branch of uterine artery near the uterine cornu in ƒ Inferior rectal the broad ligament. The right ovarian vein drains ƒ Perineal into the inferior vena cava but the left ovarian ƒ Dorsal artery of the clitoris vein joins the left renal vein. Visceral branches Ŧ Superior vesical (umbilical) Internal iliac (hypogastric) Ŧ