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Uterus, Cervix and vagina Learning objectives At the end of the lecture the student should be able to: Know the details of uterus, cervix and vagina. Enumerate the parts of uterus, ligaments of uterus and relations of uterus. Identify the clinical correlates of uterus, cervix and vagina. Female reproductive organs: Include the uterus, fallopian tubes, and the ovaries. Their position, size, and anatomic relations vary considerably with age and the physiologic changes of menstruation, pregnancy, and menopause. Uterus : Commonly referred to as the womb A pear shaped organ about the size of a clenched fist The uterus is a fibromuscular organ The uterus varies considerably in size, shape and weight depending on the status of parturition and estrogenic stimulation. Uterus is divided into: Upper 2/3 rd expanded part – body Lower 1/3 rd narrow part – cervix. Junction of the 2 parts is marked by a circular constriction. It is made up of the endometrium, myometrium and perimetrium AXIS OF UTERUS: Long axis of the uterus forms an angle of 90 degrees with the long axis of vagina. Forward bending of uterus relative to vagina is called anteversion. The uterus is also slightly bent on itself ---this is referred to as anteflexion. Angle of anteflexion is 120 degrees. BODY OF UTERUS: Fundus 2 surfaces Anterior surface Posterior surface 2 lateral borders FUNDUS Formed by upper free end of uterus Convex in all directions Covered by peritoneum continuous with that on the vesical and intestinal surfaces Directed forwards when the bladder is empty Fertilized ovum is implanted in its posterior wall. SURFACES OF UTERUS ANTERIOR / VESICAL SURFACE: Flattened Covered by peritoneum, this is reflected on to the bladder to form the vesicouterine pouch The surface lies in apposition with the bladder. POSTERIOR / INTESTINAL SURFACE: Convex transversely Covered by peritoneum, which is continued down on to the cervix and vagina Forms anterior wall of rectouterine pouch It is in relation with the sigmoid colon, from which it is usually separated by some coils of small intestine. Cervix Cervix (or neck of the uterus) is the lower, narrow portion of the uterus where it joins with the top end of the vagina Cylindrical or conical in shape It is called "cervix uteri". Cervix means neck in Latin Parts of cervix The cervix projects through the anterior wall of the vagina, which divides it into: An upper, supravaginal portion. A lower, vaginal portion. Supravaginal part is related: Anteriorly-- bladder Posteriorly — rectouterine pouch and rectum. Laterally– ureter and uterine artery Parametrium is most abundant near cervix and vagina. Vaginal part of cervix Projects free into the anterior wall of the vagina between the anterior and posterior fornices. On its rounded extremity is a small, depressed, somewhat circular aperture, the external orifice of the uterus, through which the cavity of the cervix communicates with that of the vagina. Cervical canal Endocervical canal The passageway between the external os and the uterine cavity Somewhat fusiform Flattened anterior to posterior The endocervical canal measures 7 to 8 mm at its widest in reproductive-aged women. Internal os The endocervical canal terminates at the internal os which is the opening of the cervix inside the uterine cavity. Ectocervix and endocervix Ectocervix : The portion projecting into the vagina 3 cm long and 2.5 cm wide The ectocervix (more distal, by the vagina) is composed of nonkeratinized stratified squamous epithelium. The endocervix (more proximal, within the uterus) is composed of simple columnar epithelium. Transformation zone: The area adjacent to the border of the endocervix and ectocervix is the transformation zone It undergoes metaplasia numerous times during normal life. When the endocervix is exposed to the harsh acidic environment of the vagina it undergoes metaplasia to squamous epithelium which is better suited to the vaginal environment. When the ectocervix enters the less harsh uterine area it undergoes metaplasia to become columnar epithelium. Function of cervix During menstruation the cervix stretches open slightly to allow the endometrium to be shed. During childbirth, contractions of the uterus will dilate the cervix up to 10 cm in diameter to allow the child to pass through. Blood supply: Uterine artery: from anterior division of internal iliac artery. Ovarian artery: from the abdominal aorta. Runs tortuous course in the substance of the organ, and for their frequent anastomoses. SUPPLY: • • • • • • Uterus Vagina Medial 2/3rd of uterine tube Ovary Ureter Structures in broad ligament Lymphatic drainage • • • Upper lymphatics-from fundus and upper part of the body pass to aortic nodes and only partly to superficial inguinal nodes. Lower lymphatics from cervix pass to external iliac and sacral nodes. Middle lymphatics from lower part of body pass to external iliac nodes. Nerve supply Supplied from inferior hypogastric and ovarian plexus Sympathetic nerves (T12,L1) Parasympathetic nerves (S2,3,4) Pain sensations from body pass along sympathetic nerves. Pain sensations from cervix pass along parasympathetic nerves. Uterine ligaments Two types of ligaments • Peritoneal ligaments 1. Anterior ligament Consist of uterovesical fold of peritoneum 2. Posterior ligament Consist of rectovaginal fold of peritoneum. 3. Right and Left broad ligaments. • Fibromuscular ligaments Round ligaments of the uterus Transverse cervical ligaments Uterosacral ligaments Broad ligament They attach the uterus to lateral pelvic wall. Upper border is free, contain uterine tubes Anterior and posterior layers of peritoneum forming ligament become continuous at upper border. Lateral and inferior borders of ligament are attached to corresponding part of pelvic wall. Medial border is attached to lateral margin of uterus. Divisions of broad ligament Mesosalpinx Lie between uterine tube and ovarian ligament Mesovarium Attaches ovary to uterus Mesometrium Lie below the ovarian ligament Supports of the uterus • Primary supports Muscular or active • • • Pelvic diaphragm Perineal body. Urogenital diaphragm Fibromuscular or mechanical • • • • • Uterine axis Pubocervical ligament Tranverse cervical ligament Uterosacral ligament Round ligament of uterus Secondary supports are formed by peritoneal ligaments • • • Broad ligaments Uterovesical fold of peritoneum Rectovaginal fold of peritoneum Uterine fibroid Benign (non-cancerous) tumor that originates from the smooth muscle layer (myometrium) and the accompanying connective tissue of the uterus Cervical cancer Human papillomavirus (HPV) infection is a necessary factor in the development of nearly 70% cases of cervical cancer. Potentially pre-cancerous changes in the cervix can be detected by a Pap smear Worldwide, cervical cancer is the 5th most deadly cancer in women The Papanicolau test (also called Pap smear, Pap test, cervical smear, or smear test) is a screening test used in gynecology to detect premalignant and malignant (cancerous) processes in the ectocervix Cervical polyp A cervical polyp is a common benign polyp or tumour on the surface of the cervical canal. Can cause irregular menstrual bleeding but often show no symptoms. Treatment consists of simple removal of the polyp About 1% of cervical polyps will show neoplastic change which may lead to cancer VAGINA Is a fibromuscular canal EXTENT: From vulva---to the uterus SITUATION: Situated behind the bladder and in front of the rectum 6 to 7.5 cm (2.5 to 3 in) across the anterior wall (front) and 9 cm (3.5 in) long across the posterior wall Its axis forming an angle of over 90°, with uterus Lumen- at the upper end = circular (b/c of the protusion of the cervix into it) In middle part = transverse slit (Anterior posterior walls are in contact) In lower part = H shaped In virgins Lower end is closed by a thin annular fold of mucus membrane called the hymen In married women: Hymen is represented by rounded elevations called caruncular hymenale Vagina Upper end is slightly expanded Interior of the upper end of vagina is in the form of circular groove that surrounds the protuding cervix The groove becomes progressively deeper from before backwards The groove is divided into 4 parts: Anterior fornix-shallowest Posterior fornix-deepest 2 lateral fornix-1 on each side Relations of vagina Anterior surface Upper half -- bladder Lower half -- urethra Posterior surface Upper ¼seperated from bladder by rectouterine pouch Middle 2/4 seperated from Rectum by loose C.T Lower1/4 seperated from anal canal by perineal body 7muscles attached to it Lateral surface Levator ani muscle Blood supply Main artery = Vaginal artery Additional arteries = Uterine artery Middle rectal artery Uterovaginal venous plexus Lymph drainage Upper 1/3external L.N Middle 1/3internal iliac L.N Lower 1/3medial group of inguinal L.N NERVE SUPPLY Lower 1/3pain sensitive Pudendal nerve through inferior rectal & posterior branches of perineal nerves Upper 1/3 pain insensitive Sympathetic Septate vagina A vaginal septum is a congenital partition within the vagina; such a septum could be either longitudinal or transverse.
