OB Anatomy of the Female Reproductive Tract PDF

SECTION ANATOMY OF THE FEMALE REPRODUCTIVE TRACT ONE I ANATOMY OF THE FEMALE R...

SECTION ANATOMY OF THE FEMALE REPRODUCTIVE TRACT ONE I ANATOMY OF THE FEMALE REPRODUCTIVE SYSTEM Organs of the female reproductive tract are divided into the external and internal genitalia (see below) Reproductive organs are in intimate contact with the lower urinary tract & large intestines Uterine cavity Cervix Fallopian tube Fimbriae Ovary Bladder ll':ltr-:-+s------h~'llf--+----- Cervix \\..,_.....,.,.,..."':;,fi1'f--.W-------f'+-------+ Vagina '\..-4---,-tl½-I------+ Urethra 1/--:::~~~~~,------ Rectum I. SUBDIVISIONS OF THE FEMALEREPRODUCTIVE ORGANS EXTERNAL GENITALIA (outside the true pelvis) I INTERNAL GENITALIA (within the true pelvis) Perineum Vagina Mons pubis Cervix Clitoris Uterus Urethral (urinary) meatus Uterine (fallopian) tubes Labia majora and minora Ovaries Vestibule Greater vestibular (Bartholin) glands Skene glands Periurethral area 3 II. HOMOLOGOUS STRUCTURESBETWEENMALE& FEMALEREPRODUCTIVESYSTEMS Sex determination involves genetic, gonadal, and phenotypic sex: 0 Genetic sex (XXor XY): established at fertilization 0 Gonadal sex: heralded by differentiation of the primordial gonad into a testis or an ova1y Phenotypic sex: differentiation of genitalia to the male phenotype is dependent on testicular function (in the absence of a testis, female differentiation ensues) I MALE I FEMALE Genital ridge Testis Ovary Epididymis, ductus deferens, Mesonephric ducts Gartner duct ejaculatory duct Paramesonephric Prostatic utricle, appendix Uterus, fallopian tubes, upper ducts of testis vagina Glans penis Glans clitoris Genital Tubercle Corpus cavernosum and Vestibular bulb spongiosum Cowper glands Bartholin glands Urogenial sinus (bulbourethral) Skene glands (paraurethral) Prostate gland Urogenital folds Ventral shaft of penis Labia minora Labioscrotal swelling Scrotum Labia majora VULVA (PUDENDA) Term used to describe the external organs visible in the perinea! area Includes all structures visible externally from the mons pubis to the perinea! body Labia minora (paired) -----+------+_,,-r:.~IM---+-- Urethral meatus ~·1,,11r-1f-.+-- Vestibule --,F-++----"~t. 'hwrr--.i~+~- Vagina I orifice Structures of the Vulva: Mons pubis Hymen Clitoris Vaginal opening Urinary meatus Urethral opening Labia majora and minora Glandular structures Vestibule I.MONS PUBIS Rounded fatty prominence anterior to the pubic symphysis, pubic tubercles, and superior pubic rami Formed by a mass of fatty subcutaneous tissue covered with pubic hairs after puberty Surface is continuous with the anterior abdominal wall 4 II. LABIA MAJORA AND MINORA Description I LABIA MAJORA Two longitudinal folds of adipose & fibrous tissue which extend I LABIA MINORA Two small cutaneous folds between the labia majora and the I from mons pubis to perinea) body introitus ( or vaginal vestibule) Lining Outer: KSSE NKSSE epithelium Inner: NKSSE Lie in close apposition Nulliparous Not visible behind the Inner surface resembles the women non-separated labia majora mucous membrane Multiparous Gape widely Project beyond the labia majora women Inner surface become skin-like With hair follicles No hair follicles Glands With sweat glands No sweat glands With sebaceous glands With sebaceous glands KSSE:keratinizing stratifiedsquamousepithelium NKSSE:non-keratinizing stratifiedsquamousepithelium III. HYMEN Thin membrane (NKSSE) at the entrance of the vaginal orifice that is normally perforated to allow egress of menstrual blood and secretions During first coitus, laceration usually occurs at the 6 o'clock position Caruncle myrtiformes: remnants of hymen in adult female IV. CLITORIS Erectile structure found beneath the anterior joining of the labia minora Very sensitive structure made up of glans, a corpus or body and two crura, which attach to the periosteum of the ischiopubic rami V. VESTIBULE Almond shaped area between the clitoris and the vaginal introitus (opening) Functionally mature female structure of the urogenital sinus of the embryo Extends from clitoris to posterior fourchette A. Glandular Structures in the Vestibule PERIURETHRAL GLANDS VULVOVAGINAL GLANDS I "Skene glands" I "Bartholin glands" Other name Lesser vestibular glands Greater vestibular glands Type of gland Tubuloalveolar Compound alveolar/ compound acinar Location Adjacent to the urethra 5 and 7 o'clock of the vagina Pathology Urethral diverticulum Bartholin cyst/ abscess Responsible for lubrication to the Secrete lubrication at the vagina, with openings just outside Function opening of the urethra the hymen, bilaterally, at the posterior aspect of the vagina 8. Six Openings in the Vestibule 0 Vaginal introitus 0 Urethral opening 0 Paired Skene glands opening 0 Paired Bartholin ducts opening s INTERNAL GENITALIA Intramural Isthmus ,-----, segment -----~ Ampulla[ Uterine body ,,·.-z.--.- Infundibulum[ Uterine FimbriaeC isthmus *Endocervical Lateral fornix ---~ canal External os ------#--' I. VAGINA Thin-walled, distensible, fibromuscular tube, 7-10 cm long that extends from the vestibule of the vulva to the cervix Lined by rugae, which are situated in folds throughout Rugae in reproductive aged women has an accordion-like distensibility A. Borders of the Vagina Vesicovaginal septum Separates the vagina from the bladder and urethra Rectovaginal septum Separates the lower portion of the vagina from the rectum Rectouterine pouch of Separates the upper portion of the vagina from the rectum Douglas Subdivided into anterior, posterior, and two lateral fornices Upper vaginal vaults by the uterine cervix Posterior fornix provides surgical access to the peritoneal cavity B. Supply and Support I UPPER 1/3 I MIDDLE 1/3 I LOWER 1/3 Uterine or inferior Ce,·vical branch of the vesical arteries Internal Blood uterine artery Internal iliac artery pudenda) supply Vaginal artery Middle rectal artery artery (posterior vaginal wall) Internal, external, Lymphatics Internal iliac nodes Inguinal nodes common iliac nodes General Sympathetic via hypogastric plexus Nerves somatic via the Parasympathetics via S2-S4 (low density) pudenda) nerve Levator ani muscle and transverse cervical, Support Urogenital diaphragm Perinea! body pubocervical and sacrocervical ligaments 6 II. CERVIX It is the !owe, and narrow portion of the uterus May vary in shape from cylindric to conical Usually 2.5-3 cm in length and 7-8 mm at its widest point Cervical canal opens into the vagina at the external os of the cervix I Cervical canal opens into the uterine cavity at the internal os of the cervix A. Histology ° Consists of predominantly fibrous tissue (in contrast to the primarily muscular corpus of the uterus) 0 The transformation zone encompasses the transition from stratified squamous epithelium to columnar epithelium (most cervical dysplasia develops within this transformation zone) B. Parts of the Cervix 0The vagina is attached obliquely around the middle of the cervix, dividing the cervix into: Upper portion: supravaginal portion Lower segment: portio vaginalis I ENDOCERVlX I ECTOCERVIX Location Supravaginal portion Portie vaginalis Extends from the isthmus Extends from the squamo- (internal OS) to the ectocervix Extent columnar junction to the and contains the endocervical external orifice canal Single layer of mucus-secreting highly ciliated columnar Non-keratinized stratified Histology epithelium which is thrown into squamous epithelium folds forming complex glands Hormone-sensitive and crypts Nervous supply Extensive amount of nerves Few nerves only Blood supply Cervicovaginal branch of uterine artery located at the lateral walls II. UTERUS Thick-walled, hollow, muscular organ located centrally in the female pelvis Nullipara: ~8 cm long, 5 cm wide, and 2.5 cm thick and weighs 40-50 g Multipara: each measurement is approximately 1.2 cm larger and uterine weight is 20-30 g heavier The maximal weight of a normal uterus is 110 g A. Blood Supply, Lymphatic Drainage and Nerve Supply Uterine artery from internal iliac 0 Travels medially across pelvic floor then crosses the ureter Arterial supply superiorly 0 To reach the uterus, it will pass above the vagina's lateral fornix Ovarian artery Venous drainage Uterine vein (going to internal iliac vein) and ovarian vein Lymphatic Paraaortic nodes: fundus drainage Internal and external iliac nodes: body and cervix Innervation Inferior hypo gastric plexus 7  B. Histolol!V Stratum Functionale Responds to fluctuating hormonal levels Zona spongiosa Shed during menstruation Supplied by the spiral arteries Endometrium Zona compacta Superficial 2/3 Stratum Basale Supplied by the straight arteries Basal 1/3 Inner longitudinal Myometrium Middle oblique Outer longitudinal ("hood-like" pattern) Serosa Visceral peritoneum C. Sections of the Uterus Area between the corpus uteri & the cervix (cervico-corporeal junction) Short area of constriction in the lower uterine segment Isthmus lsthmus/cervicocorpal junction: during pregnancy, this is the area that enlarges (28 weeks onwards] and becomes very dynamic (i.e., undergoes thinning, stretching) Rounded/dome-shaped portion on the top of the uterus (above a Fundus plane connecting the two fallopian tubes) Active segment: upper 2/3 of uterus where muscles are thick and participates in contraction of uterus Corpus Uteri Passive segment: lower 1/3 of the uterus where myometrium is thinner & does not participate in contraction (the former isthmus becomes the lower uterine segment) III. FALLOPIANTUBES The paired uterine tubes extend outward from the superolateral portion of the uterus and open outwardly in close approximation to the ovaries They are between 10 & 14 cm in length and slightly