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

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Presentation on theme: "MOB TCD Review of Pevic Anatomy for Gynaecologists Professor Emeritus Moira O’Brien FRCPI, FFSEM, FFSEM (UK), FTCD Trinity College Dublin."— Presentation transcript:


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

3 Female Pelvis Smout et al., 1969 MOB TCD

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

5 Pubic Symphysis 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 MOB TCD

6 Sacroiliac Joint 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 MOB TCD

7 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 Sacroiliac Joint Accessory Ligaments MOB TCD

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

9 Walls of Pelvis 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 MOB TCD

10 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 Lateral Walls of Pelvis MOB TCD

11 Pelvic Fascia 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 MOB TCD

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

13 Pelvic Ligaments 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 MOB TCD

14 Pelvic Floor 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 MOB TCD

15 Deep Perineal Pouch: Urogenital Diaphragm 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 superficial pouch deep pouch sphincter urethrae MOB TCD perineal membrane

16 Levator Ani 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 MOB TCD

17 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

18 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

19 Levator Ani 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 MOB TCD

20 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 Levator Ani MOB TCD

21 Empty Female Bladder 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 MOB TCD

22 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 Female Bladder MOB TCD

23 Control of Micturition 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, MOB TCD

24 Structure of Female Urethra 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 MOB TCD

25 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

26 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 Urethra MOB TCD

27 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 MOB TCD

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

29 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 MOB TCD

30 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 Cervix MOB TCD

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

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

33 Pubocervical Ligament 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 MOB TCD

34 Transverse Ligament 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 MOB TCD

35 Uterosacral Ligament 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 MOB TCD

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

37 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 Blood Supply MOB TCD

38 Embolization of Fibroids 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 MOB TCD

39 Lymphatics of Uterus and Vagina MOB TCD

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

41 Broad Ligament 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 MOB TCD

42 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 Contents of Broad Ligament MOB TCD

43 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

44 Broad Ligament MOB TCD

45 Uterine Tube 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 MOB TCD

46 Ovary 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 MOB TCD

47 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 MOB TCD

48 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 Ovary MOB TCD

49 Vagina 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 MOB TCD

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

51 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

52 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 superficial Vagina MOB TCD

53 Perineum perineal body central point of perineum MOB TCD

54 Peritoneum on Uterus and Vagina 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 MOB TCD

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

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

57 Pelvic Plexus 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 MOB TCD

58 Pelvic Parasympathetic 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 MOB TCD

59 Rectum 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 MOB TCD

60 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 Rectum MOB TCD

61 Blood Supply of Rectum 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 MOB TCD

62 Anal Canal 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 MOB TCD

63 Muscles of Anal Canal 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 MOB TCD

64 Peri Anal Fascia 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 MOB TCD

65 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 Anal Canal MOB TCD

66 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 MOB TCD

67 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 Inferior rectal nerve S3,4 Muscles of Anal Canal MOB TCD

68 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 Anal Canal MOB TCD

69 Blood and Nerve Supply 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 MOB TCD

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

71 Lymphatic Drainage 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 MOB TCD

72 Anal Sphincters 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 MOB TCD

73 Anal Sphincters 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 MOB TCD

74 Ischiorectal Fossa 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 MOB TCD

75 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 Ischiorectal Fossa MOB TCD

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

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

78 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.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.rectal prolapserectoceleperineal herniaanismusConstipation MOB TCD

79 “BMJ Publishing Group Limited (“BMJ Group”) 2012. All rights reserved.”

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