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Review of Pevic Anatomy for Gynaecologists MOB TCD Review of Pevic Anatomy for Gynaecologists Professor Emeritus Moira O’Brien FRCPI, FFSEM, FFSEM (UK), FTCD Trinity College Dublin

Female Pelvis MOB TCD Smout et al., 1969

Overview Bones Broad ligament Joints Ovary Fascia Vagina Muscles MOB TCD Bones Broad ligament Joints Ovary Fascia Vagina Muscles Rectum Bladder Anal Canal Urethra Uterus

Pubic Symphysis Secondary cartilagenous joint MOB TCD Secondary cartilagenous joint Articular surface of medial aspect of body of pubis Covered with hyaline articular cartilage Disc of fibro-cartilage in between A cavity may develop in the disc but it is not lined with synovial membrane There is normally very little movement at the pubic symphysis, except during the latter months of pregnancy

Sacroiliac Joint Modified synovial plane joint MOB TCD Modified synovial plane joint Articular surfaces are rough The capsule is attached just beyond the articular margin The interosseous sacroiliac ligament is one of the strongest ligaments in the body and is posterior to the joint This articulation is almost immobile, except during pregnancy

Sacroiliac Joint Accessory Ligaments MOB TCD Sacrotuberous ligaments Sacrospinous ligaments Iliolumbar ligaments Posterior superior iliac spine is middle of the joint posteriorly at the level S2 S2 is end of dura, arachnoid mater and subarachnoid space During gait, the amount of accessory movement at the sacroiliac joint helps to protect the lumbar intervertebral discs

Abnormalities of Pelvis MOB TCD Spina bifida occulta Unilateral lumbarisation Unilateral sacralisation Stress fractures of the sacrum, pubic arch and neck of femur may be first signs of osteoporosis

Walls of Pelvis Sacrum and coccyx posterior Os coxae below pelvic brim MOB TCD Sacrum and coccyx posterior Os coxae below pelvic brim Piriformis covers middle three pieces of sacrum Passes out of the pelvis through the greater sciatic foramen Muscles Obturator internus muscle Origin of levator ani Coccygeus Smout et al., 1969

Lateral Walls of Pelvis MOB TCD Obturator nerve Obturator artery and vein Parietal peritoneum supplied by the obturator nerve Pain may be referred to hip or knee joints Common iliac divides into external and internal iliac Internal divides into anterior and posterior division branches Smout et al., 1969

Pelvic Fascia Pelvic fascia can be divided into three: 1. Pelvic wall MOB TCD Pelvic fascia can be divided into three: 1. Pelvic wall Pelvic fascia is a strong membrane over the piriformis and obturator internus Fuses with the periosteum at their margins 2. Pelvic floor Fascia is covered with loose areolar tissue Loose areolar fat tissue lies in the extraperitoneal space between peritoneum and the viscera forming a dead space

Pelvic Fascia 3. Pelvic viscera MOB TCD 3. Pelvic viscera Fascia of pelvic viscera is loose or dense depending on dispensability of organ Smout et al., 1969

Pelvic Ligaments MOB TCD Condensation around vessels form ligaments in the pelvis Cardinal ligament condensation of fascia around uterine artery Lateral ligament of the rectum is a condensation of fascia around the middle rectal vessels and branches of the hypogastric plexus Waldyer’s fascia suspends the lower part of the ampulla of the rectum to the hollow of sacrum Contains the superior rectal vessels and lymphatics Smout et al., 1969

Pelvic Floor Urogenital diaphragm MOB TCD Urogenital diaphragm Perineal membrane and the superficial transverse perineii The pelvic floor is a dome-shaped striated muscular sheet The levator ani is made up mainly of the pubococcygeus, the puborectalis and the iliococcygeus It encloses the bladder, uterus and rectum Together with the anal sphincters, has an important role in regulating storage and evacuation of urine and stool Stoker, 2009

Deep Perineal Pouch: Urogenital Diaphragm MOB TCD perineal membrane Superior is the areolar tissue on the under surface of the levator ani The sphincter urethrae around urethra and transverse perineii in the deep pouch Perineal membrane fills in pubic arch below the muscles Muscles are supplied by perineal branch of pudendal nerve In lateral portion of the deep pouch, run dorsal nerve of clitoris and internal pudendal artery and vena commitans deep pouch sphincter urethrae superficial pouch

Levator Ani MOB TCD Arises, anteriorly, from the posterior surface of the body of pubis lateral to the symphysis Posterior from the inner surface of the spine of the ischium Between these two points, from a tendinous arch called the white line (arcus tendineus) adherent to the obturator fascia Last,1984

Levator Ani MOB TCD Unites with the opposite side to form most of the floor of the pelvic cavity The fibres pass downward and backward to the middle line of the floor of the pelvis Inserted from before backwards, into perineal body Side of the rectum and anal canal Anococcygeal raphe The side of the last two segments of the coccyx Last 1984

Levator Ani MOB TCD The anterior fibres, pubovaginalis, pass behind the vagina, unites with the opposite side Inserted into the perineal body, the central point of the perineum Joining the fibres of the sphincter ani externus and transversus perineii Last 1984

Levator Ani MOB TCD The puborectalis forms a U-shaped sling, holding the anorectal anteriorly, blending with the deep fibres of the external anal sphincter Anococcygeal raphe lies between the coccyx and the margin of the anus Nerve supply, inferior rectal nerve and perineal branch fourth sacral Last 1984

Levator Ani MOB TCD In women, the levator muscles or their nerve supply, can be damaged in pregnancy or childbirth There is some evidence that these muscles may also be damaged during a hysterectomy Pelvic surgery using the "perineal approach" (between the anus and coccyx) is an established cause of damage to the pelvic floor. This surgery includes coccygectomy 

Empty Female Bladder MOB TCD Bladder has a apex, triangular superior surface, base and two inferolateral surfaces, neck inferiorly Posterior or base is fixed, the two ureters enter obliquely at the junction of the superior surfaces and base The internal urethral orifice or neck is at the junction of the base and two inferolateral surfaces The interior of the bladder is lined with transitional epithelium which is thrown into folds in the empty bladder, except for the smooth triangular area of base called trigone

Female Bladder MOB TCD Pubo vesical ligaments connect the neck to the pubic bone Base is attached to the supravaginal portion of the cervix and anterior fornix of vagina Peritoneum only covers superior surface Blood supply, superior and inferior vesical arteries Venous plexus into internal iliac vein

Control of Micturition MOB TCD Smooth or detrusor muscle at the neck is the internal sphincter, supplied by the sympathetic Parasympathetic contracts detrusor muscle and relaxes internal sphincter Sphincter urethra or external sphincter is striated muscle Supplied by perineal branch of pudendal nerve S2,3,4,

Structure of Female Urethra MOB TCD Urethra 3-5 cm long Enters deep pouch where it is surrounded by Sphincter urethra, also called external sphincter of bladder Urethra pierces perineal membrane No fascia between lower two thirds of urethra and vagina Opens into vestibule, between clitoris and vagina

Urethra Muscular layer continuous with bladder Spongy erectile tissue MOB TCD Muscular layer continuous with bladder Spongy erectile tissue Plexus of veins Mucous membrane transitional Distal non keratinising stratified squamous Para urethral glands and ducts open into urethra, homologues of prostatic glands Smout et al 1969

Urethra MOB TCD Urethra is supported by the fascia of the pelvic floor including pubo- vesical and pubocervical ligaments If this support is insufficient, the urethra can move downwards In times of increased abdominal pressure resulting in stress urinary incontinence (SUI) The physical changes that can occur during pregnancy, delivery and menopause can predispose to SUI Nuggaard and Heit in Bayliss 2010

Uterus Normal uterus is anteverted MOB TCD Normal uterus is anteverted i.e. anterior to vertical plane going through the vagina Posterior fornix deeper Anteflexed Bent anteriorly junction of body and cervix Pear-shaped muscular organ 8 cm long; 5 cm width; 3 cm thick Non-pregnant state Pelvic organ

Uterus Fundus Body Cervix opens into vault or fornices of vagina MOB TCD Fundus Body Cervix opens into vault or fornices of vagina Fundus is the portion above entrance of uterine tubes Covered with peritoneum Triangular cavity

Cervix MOB TCD Isthmus is a circular borderline area between the body and cervix Isthmus is the supra vaginal portion of cervix, the lower uterine segment Intravaginal is surrounded by gutter by fornices of vagina, Posterior is deeper covered with peritoneum Internal os is the opening from the cavity of body Spindle shaped cavity cervix External os is the opening into vagina

Cervix Cervical canal is lined by columnar epithelium External os MOB TCD Cervical canal is lined by columnar epithelium External os Junction of columnar of the cervical canal Stratified epithelium of the intravaginal portion Site of cancer of cervix Cervical smear At birth cervix is larger than the body Fully developed Cervix is one third of body

Supports of Uterus Upper Round ligament Broad ligament anteverted MOB TCD Upper Round ligament Broad ligament anteverted Transverse ligament Pubocervical Uterosacral Lower Levator ani, coccygeus Perineal body

Round Ligament Round ligament and ligament of ovary MOB TCD Round ligament and ligament of ovary Develop from the gubernaculum Side of uterus, junction fundus and body Inguinal canal to labium majus Ante version

Pubocervical Ligament MOB TCD Attached Anteriorly to posterior aspect of body of body of pubis Passes to neck of bladder Anterior fornix of vagina Pubocervical ligaments help to Maintain normal angle of 45° between the vagina and horizontal Decrease may cause a cystocoele

Transverse Ligament Transverse or cardinal or Mackenrodt’s ligament MOB TCD Transverse or cardinal or Mackenrodt’s ligament Thickening of visceral layer of pelvic fascia around uterine artery Lateral to medial in base of broad ligament

Uterosacral Ligament Uterosacral contains fibrous tissue MOB TCD Uterosacral contains fibrous tissue Non-striated muscle Attached from the cervix to the middle of sacrum Contains lymphatics draining cervix to sacral glands Uterosacral help to keep uterus anteverted If uterus is anteverted it cannot prolapse

Blood Supply Uterine from internal iliac Ovarian from aorta at L2 MOB TCD Uterine from internal iliac Ovarian from aorta at L2 Vaginal arteries from internal iliac Anterior and posterior arcuate run in middle layer

Blood Supply Serous layer Myometrium No submucous layer Endometrium MOB TCD Serous layer Myometrium No submucous layer Endometrium Compact at surface of uterine cavity and spongy layer are supplied by spiral arteries Basal layer is not shed during menstruation; supplied by radial branches Veins below artery Plexus in lower edge broad ligament into internal iliac

Embolization of Fibroids MOB TCD Fibroids vary in size and position in uterine wall May enlarge and compress ureters or other structures in pelvis A small catheter is inserted in the groin, into the femoral artery Small particles are introduced through the catheter into the uterine artery They block the blood supply to the fibroids The fibroids thus starved of blood shrivel and die over the next few months

Lymphatics of Uterus and Vagina MOB TCD

Nerve Supply of Uterus Pain from cervix via parasympathetic S2,3 MOB TCD Pain from cervix via parasympathetic S2,3 Pain from body via sympathetic to T11 and T12

Broad Ligament MOB TCD Fold of peritoneum from side of uterus to side wall of pelvis Framework of pelvic fascia Parametric fat Anterior surface looks inferiorly Free upper border Base lies on pelvic floor

Contents of Broad Ligament MOB TCD Uterine tubes Ovarian vessels Uterine vessels Epoophoron Paroophoron Round ligament of uterus and ligament of ovary Transverse ligament Ovary attached to posterior layer Ureter in base below uterine artery

Broad Ligament MOB TCD Uterine tube lies in medial four fifths of free border of broad ligament Lateral one fifth Contains ovarian vessels Infundibulo-pelvic or suspensory ligament of ovary Epoophoron Parallel tubules remains of mesonephric tubules Gartner's duct remains of mesonephric duct, may form cysts

Broad Ligament MOB TCD

Uterine Tube Intramural Isthmus Ampulla MOB TCD Intramural Isthmus Ampulla Infundibulum surrounded by fimbria Lined ciliated columnar epithelium Beats towards uterus Peritoneum loosely attached to ampulla Tightly to isthmus, if ectopic implanted here, ruptures earlier Fimbria surrounding opening into peritoneal cavity Ovarian fimbria is longest

Ovary Attached to posterior layer of broad ligament meso ovarian MOB TCD Attached to posterior layer of broad ligament meso ovarian Covered with germinal epithelium Related to side wall of pelvis which is covered with peritoneum Obturator internus muscle Obturator nerve supplies the parietal peritoneum Posterior to ovary is the ureter Ligament of ovary medially

Ovary Obturator nerve supplies the parietal peritoneum MOB TCD Obturator nerve supplies the parietal peritoneum Irritation of the peritoneum of the side wall by bleeding at ovulation or by lesions involving the ovary May result in referred pain to medial side of the thigh or the knee

Ovary Blood supply One ovarian artery from lateral aspects of aorta L2 MOB TCD Blood supply One ovarian artery from lateral aspects of aorta L2 Right vein drains into inferior vena cava Left drains into left renal vein Lymphatics into para aortic glands L2

Vagina Fornices, gutters which surround the cervix MOB TCD Fornices, gutters which surround the cervix Normal anteverted antiflexed Anterior fornix is shallow anterior wall is shorter than posterior Posterior deeper, covered with peritoneum of the pouch of Douglas Most dependent part of peritoneal cavity Walls in contact except superior Opens into vestibule of vagina

Uterine Artery MOB TCD Uterine artery lies superior to the ureter at lateral fornix of vagina Base of broad ligament

Vagina Erectile tissue Muscular wall Pelvic fascia MOB TCD Erectile tissue Muscular wall Pelvic fascia Nonkeratinised stratified squamous epithelium Urethra lower third anterior wall No fascia between lower two thirds of urethra and vagina Upper portion of the vagina is clasped by the pubo-vaginalis portion of the levator ani

Vagina MOB TCD superficial Deep pouch Sphincter urethrae, deep transverse perineii, pierces perineal membrane, opens into vestibule of vagina Hymen fold of mucous membrane at external opening Lateral are the bulbs of vestibule Covered by bulbospongiosus muscle Greater vestibular (Bartholin's) glands lie behind the bulbs of vestibule Ducts open into orifice of the vagina Posterior to vagina is the perineal body deep pouch

Perineum MOB TCD perineal body central point of perineum

Peritoneum on Uterus and Vagina MOB TCD Reflected from the superior surface of the bladder Junction of the supravaginal portion of the cervix and the body of the uterus forming the utero vesical pouch Peritoneum then covers body, fundus and posterior surface body and then the supravaginal cervix and posterior fornix of vagina Peritoneum then reflected on to junction of upper two thirds and lower third of rectum forming Pouch of Douglas is most dependent part of female peritoneal cavity

Blood and Nerve Supply Vagina MOB TCD Uterine artery Vaginal Internal pudendal Labial Ilio Inguinal nerve supplies the anterior wall Labial nerves supply the posterior wall

Lymphatics of Vagina Internal iliac Lower third MOB TCD Internal iliac Lower third Medial group of proximal superficial inguinal glands

Pelvic Plexus Lumbar splanchnics L1-L2 Presacral nerve MOB TCD Lumbar splanchnics L1-L2 Presacral nerve Anterior to body of L5 Divide into pelvic plexuses Postganglionic of sympathetic that relayed in lumbar and sacral ganglia causes contraction of sphincters of bladder and anal canal

Pelvic Parasympathetic MOB TCD Preganglionic have cell bodies in lateral column of segments S2,3,4 Ganglia found close to or in wall of organ Supplies intestine from splenic flexure to upper two thirds of anal canal, bladder Motor to walls and inhibitory to sphincters Parasympathetic causes erection

Rectum Rectum is a continuation of pelvic colon MOB TCD Rectum is a continuation of pelvic colon Starts at the third piece of the sacrum Ends 5 cm from the tip of coccyx Lower end is dilated at the ampulla, at the anorectal junction There are no taeniae and no appendices epiplociae on the rectum

Rectum MOB TCD It has an antero-posterior curve, above it is angled anteriorly by the puborectalis Below convex forwards Three lateral curves Two concave to left, one to right, where the valves of Houston, which consist of circular muscle and mucous membrane Peritoneum covers upper third on front and sides Middle third on front, none on lower third

Blood Supply of Rectum MOB TCD Superior rectal, continuation of inferior mesenteric artery Runs in Waldyer’s fascia from hollow of sacrum to the lower part of the ampulla of the rectum Supplies mucous membrane as far mucocutaneous junction of anal canal Venous drainage into portal system Middle rectal the muscle layer Small twigs from median sacral

Anal Canal Starts at anorectal junction Below ampulla of rectum MOB TCD Starts at anorectal junction Below ampulla of rectum Passes backwards Approx 4 cm Ends at anus Anterior: perineal body Posterior: anococcygeal body Lateral: ischiorectal fossae

Muscles of Anal Canal MOB TCD The anal sphincter is a multilayered cylindrical structure The inner smooth muscle of the internal sphincter Surrounds upper two thirds Lower two thirds the outer striated muscle layer of the external sphincter Anorectal ring formed by puborectalis and the deep part of the external sphincter

Peri Anal Fascia MOB TCD Perianal fascia continuation of longitudinal coat of rectum Medial to deep and superficial external sphincters Attached at Hilton’s line Passes to lateral wall Above subcutaneous sphincter

Anal Canal MOB TCD Lateral sheet passes between soft ischiorectal fat and subcutaneous fat to lateral wall Splits to form pudendal canal and is Continuous superiorly with the lunate fascia, which passes above soft ischiorectal fat It is medial to deep and superficial sphincter Above subcutaneous sphincter

Muscles of Anal Canal MOB TCD Puborectalis portion levator ani holds the anorectal junction anteriorly Deep and subcutaneous parts of external are true sphincters No bony attachments Superficial attached to coccyx and the perineal body

Muscles of Anal Canal Anorectal ring Internal sphincter Puborectalis MOB TCD Anorectal ring Internal sphincter Puborectalis Puborectal fascia External sphincter Deep, true sphincter, no bony attachments Inferior rectal nerve S3,4 Superficial S4 Subcutaneous, true sphincter

Anal Canal Upper two thirds lined by columnar epithelium MOB TCD Upper two thirds lined by columnar epithelium Lower third by skin Junction of two is Hilton’s white line skin Anal columns contain radicles of superior rectal artery and veins 4,7,11 At the lower end joining the columns are mucosal folds called anal valves Anal sinuses lie behind Skin supplied by inferior rectal vessels and nerves

Blood and Nerve Supply Upper two thirds Columnar epithelium MOB TCD Upper two thirds Columnar epithelium Superior rectal artery Autonomic nerves Derived from cloacae Lower third Skin Inferior rectal S3,4, Somatic nerves Derived from proctodeum

Venous Drainage Mucosa upper two thirds Superior rectal vein MOB TCD Mucosa upper two thirds Superior rectal vein Portal system Lower third Inferior rectal vein Vein into systemic system Portal systemic anastomosis’ 4,7,11

Lymphatic Drainage Upper third Pre aortic inferior mesenteric MOB TCD Upper third Pre aortic inferior mesenteric Waldeyer’s fascia passes from sacrum to the ampulla of rectum Encloses superior rectal vessels and lymphatics Internal iliac Lower Third Inferior rectal cross ischio-rectal fossa Medial superficial inguinal glands

Anal Sphincters MOB TCD The internal and external anal sphincters are primarily responsible for maintaining faecal continence at rest and when continence is threatened, respectively. Defecation is a somato-visceral reflex regulated by dual nerve supply (i.e. somatic and autonomic) to the anorectum. Bharucha 2006

Anal Sphincters MOB TCD The net effects of sympathetic and cholinergic stimulation are to increase and reduce anal resting pressure, respectively. Faecal incontinence and functional defecatory disorders may result from structural changes and/or functional disturbances in the mechanisms of faecal continence and defecation. Bharucha 2006

Ischiorectal Fossa Ischiorectal fossa contents Soft ischiorectal fat MOB TCD Ischiorectal fossa contents Soft ischiorectal fat Lunate fascia above the fat Inferior rectal vessels pass above the fat to reach medial wall Perineal branch of S4 ischiorectal fossa

Ischiorectal Fossa Ischiorectal fossa contents MOB TCD Ischiorectal fossa contents lunate fascia above the soft ischiorectal fat Inferior rectal vessels and nerve pass above lunate fascia and the fat to reach medial wall Subcutaneous fat lies below perianal fascia Perineal branch of S4 Lymphatics cross fossa

Pudendal Canal Runs posterior to anterior Pudendal canal contents MOB TCD Runs posterior to anterior Pudendal canal contents Pudendal nerve Inferior rectal nerve Dorsal nerve of clitoris Perineal nerve Labial nerves Internal pudendal vessels

Pudendal Block Pudendal nerve Lies on the sacrospinous ligament MOB TCD Pudendal nerve Lies on the sacrospinous ligament Anaesthetizes posterior wall of the vagina Ilioinguinal nerve supplies the anterior wall

MOB TCD Age, pregnancy, family history, and hormonal status all contribute to the development of pelvic organ prolapse. The vagina is suspended by attachments to the perineum, pelvic side wall and sacrum via attachments that include collagen, elastin, and smooth muscle. Surgery can be performed to repair pelvic floor muscles. The pelvic floor muscles can be strengthened with Kegel exercises. Disorders of the posterior pelvic floor include rectal prolapse, rectocele, perineal hernia, and a number of functional disorders including anismus. Constipation due to any of these disorders is called "functional constipation" and is identifiable by clinical diagnostic criteria.

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