Anatomy of the Genital Tract PDF

Anatomy of the genital tract The external genetalia: is commonly called the vulva and includes the mons pubis, labia majora and minora, vaginal vestibule, clitoris and greater vestibular glands. Mons pubis: a fibrofatty pad covered by hair-bearing skin covering the bo...

Anatomy of the genital tract The external genetalia: is commonly called the vulva and includes the mons pubis, labia majora and minora, vaginal vestibule, clitoris and greater vestibular glands. Mons pubis: a fibrofatty pad covered by hair-bearing skin covering the body of pubic bones. Labia majora: two folds of skin with underlying adipose tissue lying either side of vaginal opening, contain sebaceous, sweat and few apocrine glands. Labia minora: two thin folds of skin lie between labia majora. Anteriorly, they divide in two to form the prepuce and frenulum of the clitoris. Posteriorly, they divide to form a fold of skin at the back of vaginal introitus (fourchette). They contain sebaceous glands but no adipose tissue. Clitoris: a 0.5-3.5 cm erectile structure and is made up of paired columns of erectile and vascular tissue called: corpora cavernosa. Vestibule: a cleft between the labia minora contains openings of the urethra, Bartholine’s glands and the vagina. Bartholine’s glands: are bilateral and open via a 2cm duct into the vestibule below the hymen and contribute to lubrication during intercourse. Hymen: a thin covering of mucous membrane across the entrance of the vagina. It is usually perforated to allow menstruation. It ruptures during intercourse leaving remaining tags: carunculae myrtifomes. In the pre-pubertal vulva, no hair and little adipose deposition while during puberty pubic hair develops and fat deposits within the labia. After menopause labia minora loses fat and become thinner while vaginal opening becomes smaller  Anatomy of the genital tract The external genetalia Mons pubis Labia majora Labia minora Clitoris Vestibule Bartholine’s glands Hymen The internal reproductive organs: The vagina: is a fibromuscular canal lined with stratified squamous epithelium that leads from the uterus to the vulva. It is longer in the posterior wall (9cm) than the anterior (7cm). The vault is divided into 4 fornices: posterior, anterior and 2 lateral. It has no glands and is kept moist by secretions from uterine and cervical glands and from transudation from its epithelium lining. The epithelium is thick and rich with glycogen which increases in post-ovulatory phase. The vagina is devoid of glycogen before puberty and after menopause due to lack of estrogen. Doderlein’s bacillus is the normal vaginal flora that breaks glycogen to form lactic acid and produce a PH around 4.5, which protects the vagina by decreasing pathogenic bacterial growth. The internal reproductive organs  Anatomy of the genital tract The vagina Fornices Glands Epithelium Epithelium – age Doderlein’s bacillus The upper posterior wall form the anterior peritoneal reflection of the pouch of Douglas, the middle third is separated from the rectum by the pelvic fascia and the lower third abuts the perineal body. Anteriorly it is in direct contact with the base of the bladder and the urethra. Laterally at the fornices, the vagina is related to the cardinal ligaments and below this are the levator ani muscles and the ischio-rectal fossae. The cardinal and utero-sacral ligaments supports the upper part of the vagina. At birth the epithelium is well developed (maternal estrogen influence). After few weeks the epithelium atrophies and PH is 7, at puberty the reverse occurs and after menopause the vagina shrinks and the epithelium atrophies The uterus: The uterus is like an inverted pear tapering inferiorly to the cervix and situated entirely within the pelvis (the non-pregnant state). It is 7.5cm length, 5cm width and 3cm thickness. The upper part: the body (corpus), the area of insertion of each fallopian tube: the cornu and the part of the body above the cornu: the fundus. The uterus tappers to a small constricted area: the isthmus and below this is the cervix that projects obliquely into the  Anatomy of the genital tract vagina. The constriction at the isthmus where the corpus joins the cervix: the anatomical os. The longitudinal axis is approximately at right angles to the vagina and normally tilts forward: anteversion. The uterus is usually flexed forward on itself at the isthmus: antiflexion. In about 20% of women the uterus tilts backwards: retroversion and retroflexion and this have no pathological significance. The uterus consists of 3 layers: the outer serous layer (peritoneum), the middle muscular layer (myometrium) and the inner mucous layer (endometrium). The peritoneum covers the body of the uterus and posteriorly the supra-vaginal part of the cervix. It is intimately attached to a subserous fibrous layer except laterally where it spreads out to form the leaves of the broad ligament. The uterus Situation – size Parts Anteversion. Antiflexion. Retroversion. Retroflexion  Anatomy of the genital tract Layers: 1. Serous 2. Muscular 3. Mucous Myometrial layers Endometrium The external layer of myometrium is longitudinal; the larger intermediate layer has interlacing longitudinal, oblique and transverse fibers while the inner layer is mainly longitudinal and circular. The endometrium covered by a single layer of columnar epithelium, undergoes cyclic changes during menstruation and varies in thickness from 1-5mm. The cervix Length Parametrium Pritoneum Involuntary muscles Fibrous connective tissue.  Anatomy of the genital tract Glands Epithelium The cervix: The cervix is narrower than the uterus, about 2.5cm length. Lateral to the cervix lies a cellular connective tissue: parametrium, the ureter runs about 1cm laterally to the supra vaginal cervix within the parametrium. The posterior aspect of the cervix is covered by the peritoneum of the pouch of Douglas. Its upper part consists of involuntary muscles while the lower part is mainly fibrous connective tissue. It has deep glandular follicles that secrete clear alkaline mucous (main component of physiological vaginal discharge). The cervical canal (endocervix) epithelium is columnar and also ciliated in the upper two thirds, this change to stratified squamous epithelium around the region of the external os and the junction of these two types of epithelium is called: sqamocolumnar junction or transformation zone. The fallopian tubes Extension Length Parts Epithelium: ciliated secretory Muscles The fallopian tubes:  Anatomy of the genital tract The fallopian tubes extend outwards from the cornu to end near the ovary. It runs in the upper margin of the broad ligament (mesosalpinx), the tube is completely covered with peritoneum except for a narrow strip along its inferior aspect. It is about 10cm length. It has 4 parts: 1.The interstitial portion: lies within the wall of uterus. 2.The isthmus: the narrow part adjoining the uterus. 3.The ampulla: the widest and longest part. 4.The fimbrial portion (infundibulum): opens into the peritoneal cavity. It is surrounded by finger-like processes: the fimbria, into which the muscle coat does not extend. The muscles of the tube are arranged in inner circular and outer longitudinal layer. The epithelium contains 2 functional cell types: the ciliated cells (produce current of fluid in the direction of the uterus) and secretary cells (contribute to the volume of tubal fluid), these cells undergo changes during menstruation but no shedding occurs. The ovaries Size and appearance Peritoneum Ovarian ligament Mesovarium Suspensory ligament Infundibulo-pelvic fold  Anatomy of the genital tract The ovaries: The size and appearance of the ovaries depends on the age and stage of the menstrual cycle; they are small (1.5cm) in a child, they increase to adult size at puberty due to proliferation of stromal cells and follicle maturation (3cm length, 1cm width and 1cm thickness). After menopause they are small with wrinkled surface since no active follicles are present. It is the only intra-peritoneal structure not covered by peritoneum. It is attached to the cornu of the uterus by the ovarian ligament and at the hilum to the broad ligament by the mesovarium which contains its nerves and blood vessels. Laterally each ovary is attached to the suspensory ligament of the ovary with folds of peritoneum which becomes continuous with that of the psoas muscles. The part of the broad ligament that is lateral to the fallopian tube opening: infundibulo- pelvic fold, where the ovarian vessels and nerves pass from the side wall of the pelvis to lie between the 2 layers of the broad ligament. It has a central vascular medulla (connective tissue contain elastin fibers and non-striated muscles) and an outer thicker cortex (network of reticular fibers and fusiorm cells) with no clear-cut demarcation between the 2 layers. The surface is covered by a single layer of cuboidal cells (the germinal epithelium) beneath it is ill-defined layer of connective tissue (tunica albuginea) which increase in density with age. Vestigial structures Epoophoron Paroophoron  Anatomy of the genital tract The duct of Gartner Vestigial structures: Vestigial remains of the mesonephric ducts and tubules always present in young children but are variable structures in adults. The epoophoron: a series of parallel blind tubules lie in the broad ligament between the mesovarium and fallopian tube. The paroophoron: a few rudimentary tubules situated in the broad ligament between the epoophoron and the uterus. The duct of Gartner: is the caudal part of the mesonephric duct, it runs alongside the uterus to the internal os. The pelvic muscles, ligaments and fascia:  Anatomy of the genital tract The pelvic diaphragm: The pelvic diaphragm is formed by the levator ani muscles: broad and flat muscles with their fibers passing downwards and inwards constituting the pelvic diaphragm. They arise by linear origin from: 1.Lower part of the body of the os pubis. 2.Internal surface of parietal pelvic fascia along the white line. 3.Pelvic surface of ischial spine. They are inserted into: 1.The perineal raphe and central point of the perineum where one muscle meets the other on the opposite side. 2.The wall of the anal canal where the fibers blend with the deep external sphincter muscles. 3.The postanal or anococcygeal raphe where one muscle meets the other on the opposite side. 4.The lower part of the coccyx. The muscle is described in two parts: 1.The pubococcygeus: arise from pubic bone and the anterior part of the tendinous part of the pelvic fascia (white line). 2.The iliococcygeus: arise from the posterior part of the tendinous arch and the ischial spine. The medial border of pubococcygeus muscle pass from either side from pubic bone to the preanal raphe embracing the vagina and on contraction have some sphincteric action. These muscles support pelvic and abdominal viscera including the bladder, their medial edge pass beneath the bladder and laterally to the urethra where some of its fibers inserted forming a loop maintaining the angle between the posterior aspect of the urethra and bladder base which, during micturition, relaxes to allow the bladder neck and upper urethra to open and descend. The pelvic diaphragm Levator ani muscles  Anatomy of the genital tract Origin 1.Pubic body 2.White line 3.Ischial spine Insertion 1.The perineal raphe and central point of the perineum where one muscle meets the other on the opposite side. 2.The wall of the anal canal where the fibers blend with the deep external sphincter muscles. 3.The postanal or anococcygeal raphe where one muscle meets the other on the opposite side. 4.The lower part of the coccyx. 1.Pubococcygeus 2.Iliococcygeus Sphincteric action Support pelvic and abdominal viscera including the bladder  Anatomy of the genital tract The perineal body Muscular tissue lies between the anal canal and lower third of the vagina, its apex is at the lower end of the rectovaginal septum where the rectum and posterior vaginal walls come in contact and its base extends from the fourchette to the anus and covered with skin. It is the point of insertion of the superficial perineal muscles and bounded above by levator ani muscles where they come into contact in the midline between posterior vaginal wall and rectum. The pelvic peritoneum Anteriorly Laterally Posteriorly Rectum The pelvic peritoneum:  Anatomy of the genital tract Anteriorly, the uterus is covered with peritoneum only as far as the level of internal os, below this it is reflected onto the bladder forming the uterovescical pouch. The supravaginal cervix below this is separated from the bladder by connective tissue. The uterus is completely covered with peritoneum except a narrow area laterally where the peritoneum sweeps to form the broad ligament. Posteriorly the peritoneum covers the posterior surface of cervix and upper third of posterior vaginal wall forming the anterior boundary of the rectovaginal pouch of Douglas then reflects to the rectum where the front and sides are covered by the peritoneum of rectovaginal pouch of Douglas, the middle third only the front is covered and the lower third, no peritoneal covering and the rectum is separated from the vagina by rectovaginal fascial septum. The peritoneum is reflected from the lateral borders of the uterus to form on either side a double fold of peritoneum: broad ligament (it is not a ligament but a peritoneal fold and does not support the uterus). The ovarian ligament: lies beneath the posterior layer of the broad ligament from the medial pole of the ovary to the uterus just below the point of entry of fallopian tubes. The round ligament: is the continuation of the same structure and runs forward under the anterior leaf of peritoneum to enter the inguinal canal ending in the subcutaneous tissue of labia majora. The pelvic fascia The cardinal ligaments The utero-sacral ligaments The bladder support  Anatomy of the genital tract The pelvic fascia: The parietal pelvic fascia lines the wall of the pelvic cavity covering obturator and pyramidalis muscles. There is a thick tendinous arch on the side wall of the pelvis (white line) from which levator ani muscles arises and cardinal ligaments gain lateral attachment. It forms the upper layer of the urogenital diaphragm. Important parts of visceral fascia: The cardinal ligaments (transverse cervical ligaments): are 2 strong fan-shaped fibromuscular bands passes from the cervix and vaginal vault to the side wall of the pelvis; they provide the essential support of the uterus and vaginal vault. The utero-sacral ligaments: run from the cervix and vaginal vault to the sacrum. The bladder is supported laterally by condensation of visceral pelvic fascia on each side and by a sheet of pubocervical fascia which lies beneath it. Pelvic blood supply 1.The ovarian artery 2.The internal iliac artery a.The uterine artery anastomose with ovarian artery  Anatomy of the genital tract supply uterus, ureter, cervix and upper vagina b.The vaginal artery c.The vescical arteries Pelvic blood supply: 1.The ovarian artery arise from the aorta below the renal artery (because the ovary develops on the posterior abdominal wall and later migrates to the pelvis, it carries its blood supply from the abdominal aorta). The artery divides into branches that supply the ovary and tube and then anastomoses with the terminal branches of uterine artery. 2.The internal iliac artery begins at the bifurcation of the common iliac artery, divides to anterior and posterior branches: the branches that supply the pelvic organs are all from the anterior division. a.The uterine artery provides main blood supply of the uterus, from the base of the broad ligament it runs to the upper part of the uterus to anastomose with ovarian artery, in this part it send many branches into the substance of the uterus. Also supply branches to the ureter, cervix and upper vagina. b.The vaginal artery supply the vagina. c.The vescical arteries supply the bladder and terminal ureter.  Anatomy of the genital tract d.The middle rectal artery arise in common with the lowest vescical artery. e.The pudendal artery which leaves the pelvic cavity through the sciatic foramen entering the ischiorectal fossa giving the inferior rectal artery, its terminal branches supply the perineal and vulval arteries 3.The superior rectal artery: a continuation of inferior mesenteric artery that descends in the base of the mesocolon, divides into two branches supply the rectum. The pelvic veins: Venous drainage from uterine, vaginal and vescical plexus is chiefly into the internal iliac veins. Venous drainage from rectal plexus is via superior rectal veins to the inferior mesenteric veins, and the middle and inferior rectal veins to the internal pudendal and then to iliac veins. The ovarian veins begins in the pumpiniform plexus between the broad ligament layers, the right vein ends in the inferior vena cava and the left in the left renal v.. d.The middle rectal artery e.The pudendal artery inferior rectal artery perineal and vulval arteries 3.The superior rectal artery: a continuation of inferior mesenteric artery The pelvic veins: Uterine, vaginal and vescical into the internal iliac veins. Rectal plexus -superior rectal veins to the inferior mesenteric veins -middle and inferior rectal veins to the internal pudendal and then to iliac veins. The ovarian veins -right vein ends in the inferior vena cava -left in the left renal vein. The pelvic lymphatics  Anatomy of the genital tract -Lymphatic drainage from lower extremities, vulva and perineal regions is filtered through: inguinal and superficial femoral nodes then the external iliac, common iliac and para-aortic nodes. -Medially, another chain passes from the deep femoral nodes through: femoral canal to obturator and internal iliac groups. (from upper vagina, cervix and body of uterus). From the internal and common iliac nodes to para-aortic chain and into the lumbar lymphatic trunks and cisterna chyli , carried by the thoracic duct to empty into the junction of left subclavian and internal jugular veins (tumor dissemination) The cervix: internal iliac, obturator and external iliac nodes, common iliac and lower para- aortic nodes. -Uterus join those of cervix with similar nodes. A few vessels from the fundus follow ovarian vessels and others along the round ligament to inguinal nodes. -The ovaries and fallopian tubes drain to para-aortic nodes left to left renal pedicle right they flow into thoracic duct (early spread of metastatic carcinoma). Pelvic nerve supply -The pudendal nerve arise (second, third and fourth sacral nerves): inferior rectal branch divides into perineal nerve and dorsal nerve of clitoris. The perineal nerve gives the sensory supply of the vulva and also the anterior part of  Anatomy of the genital tract external anal canal, levator ani and superficial perineal muscles. -The ilioinguinal and genitofemoral nerves supply sensory fibers to mons and labia and to first lumbar root. -The posterior femoral cutaneous nerve (perineum)