Anatomy of the Female Reproductive System

Pelvis

The anterior superior edge of the first sacral vertebra is called the promontory, it protrudes slightly into the cavity of the pelvis

Pelvis Sacro-iliac joint 骶髂关节 Sacro-coccygeal joint 骶尾关节 Symphysis pubica 耻骨联合 The pelvic bone are joined by four articulations: the pubic symphysis, the sacrococcygeal jionts and the sacroiliac jionts

The pelvic floor is formed by three layers of muscles and fasciae: The superficial compartment of the perineum consists of the ischiocavernosus muscles which cover the crura leading to the clitoris; and the bulbocavernosus muscles , which extend from the central tendon of the perineum around each side of the vaginal opening to insert upon the base of the clitoris and which cover the erectile bulbs of the superficial space. Also in the superficial space are the superficial transverse perineal muscles which from the ischial tuberosities to the perineal body, the external sphincter ani , Bartholin’s glands and the perineal vessels and nerves.

mons pubis The mons pubis is composed of fibro-fatty tissue which covers the bodies of the pubis bones. It is covered with pubic hair, and divides to become continuous with labium majus of each side . THE VULVA

labia majora The most prominent features of the vulva, the labia majora , are large, hair-covered two folds of skin which merge posteriorly into the perineum where they are jioned together by the fourchette, they contain sebaceous glands and lie on either side of the introitus.

labia minora prepuce The labia minora are two thin folds of skin which lie between the labia majora , their inner surfaces are the lateral boundaries of the vestibule. Anteriorly they divide into two thin folds, the upper of which unite over the clitoris to form the prepuce , and the lower of which unite to form the frenulum. They contain no hair but have a rich supply of venous sinuses, sebaceous glands, and nerves. They are very sensitive and contain some erectile tissue. Frenulum labium pudendal Frenulum

The vestibule is the triangular area bounded anterolaterally by the labia minora and posteriorly by the fourchette. At the apex of the triangle is the clitoris. It contains the urethral meatus located approximately 2 to 3 cm posterior to the clitoris, immediately in front of the vaginal opening . Into the vestibule open the ducts of Bartholin’s glands.

Vestibular bulb are two oblong masses of erectile tissue which lie on either side of the vaginal entrance from the vestibule. Each bulb is covered by the bulbocavernosus muscle. These muscles aid in constricting the venous supply to the erectile vestibular bulbs and also act as the sphincter vaginae.

Bartholin‘s glands are two small rounded structures situated just posterior to the vestibular bulbs. During sexual excitation, they secrete a glairy fluid which serves as lubricant. Their ducts open in the groove between the labia minora and the hymen. Each duct is about 0.5cm long , and unless it is inflamed the orifice cannot usually be seen. They are often the site of gonococcal infections and painful abscesses. 开口堵塞可形成囊肿

The clitoris lies just in front of the urethra and consists of the glans, the body, and two crura. Only the glans of the clitoris is visible externally. The glans is covered with modified skin containing many nerve endings. The body extends superiorly for a distance of several centimeters and divides into two crura, which are attached to the undersurface of either pubic ramus. The body and the crura are composed of erectile tissue. Each crus is covered by the corresponding ischiocavernosus muscle and by their contraction produce erection of the clitoris.

Hymen : As the labia minora are spread, the vaginal introitus, guarded by the hymenal ring, is seen. The hymen may take many forms, however, such as perforated centrally,a cribriform plate with many small openings or a completely imperforate diaphragm, and varying in size from a pin-hole to one that admits two fingers. The hymen is partially ruptured at the first coitus and further disrupted during childbirth.

vagina Internal Genitalia uterus ovary oviduct uterine adnexa

Remnants of the mesonephric ducts may sometimes be demonstrated along the vaginal wall in the subepithelial layers and may give rise to Gartner‘s duct cysts. The vagina, anteriorly and posteriorly has multiple transverse rugae. 阴道可以伸展当胎儿通过时 The upper two-thirds of the vagina is almost vertical in its orientation. An important anatomic feature is the immediate proximity of the posterior fornix of the vagina to the pouch of Douglas, which allows easy access to the peritoneal cavity from the vagina, by either culdocentesis or colpotomy. THE VAGINA

The lower third of the vagina passes perpendicularly through the levator hiatus and the perineum, the musculature of superficial space as well as the perineal membrane. THE VAGINA During sexual excitement, the parasympathetic supply, via the pelvic nerves effects elongation of the vagina, transudation of a lubricating fluid from the vaginal mucosa, vasocongestion of the distal third of the vagina, and further lubrication from the greater vestibular glands in the vestibule of the vagina.

The cervix consists of a vaginal portion , which is easily seen during speculum examination of the vagina, and a supravaginal portion , which is very important in the endopelvic fascial support system of the cervix and upper vagina. The vaginal portion protrudes into the vagina and is surrounded by the fornices is covered with a nonkeratinizing squamous epithelium. The cervical epithelium is of tall columnar type. At about the external cervical os, the squamous epithelium covering the exocervix changes to simple columnar epithelium, the site of transition being referred to as the squamo-columnar junction, and it is at this site that carcinoma is particularly liable to arise. THE CERVIX Surrounding the supravaginal portion of the cervix is a dense ring of endo-pelvic fascia into which is anchored the pubocervical fascia, as well as the uterosacral and cardinal ligaments. This endopelvic fascial ring has also been called the “paracervical fascia.

The “paracervical ring” is the key link in the important mechanical continuity of the endopelvic fascia to the vagina and cervix from both the upper vertical and horizontal support axes. Here, both cardinal ligaments – uterosacral ligament complexes of the vertical support axis merge with the pubocervical fascia of the horizontal support axis. “ PARACERVICAL RING” THE CERVIX relationship to the vagina The cervix enters the vagina by coursing perpendicularly to the anterior vaginal wall, thus explaining the shorter length of the anterior vaginal wall [8cm] when compared to the posterior vaginal wall [10-11cm].

The uterus is typically 7 cm in length from the external os to the top of the fundus and approximately 5 cm in width at the level of the uterine ostia, which define the widest part of the uterus. The endometrial cavity is a potential space which is triangular in shape. The walls of the uterus are approximately 2.5 cm in thickness. 6 THE UTERUS

The endometrial lining of the uterine corpus may vary from 2 to 10 mm in thickness (which may be measured by ultrasound imaging), depending on the stage of the menstrual cycle. The superficial two-thirds of the endometrium which slough in menstrual period is called functional stratum. The deep layer which has no change in menstrual period is called basal stratum. THE UTERUS

In most women the uterus is anteverted, the long axis of the uterus is directed forwards. The body of the uterus is also bent forwards on the cervix(anteflexed). The opposite condition of retroversion with retroflexion is found in about 20% of normal women.

retroflexed and retroverted uterus

Four paired sets of ligaments are attached to the uterus: round ligament : inserts on the anterior surface of the uterus just in front of the fallopian tube, passes to the pelvic side wall in a fold of the broad ligament, traverses the inguinal canal, and ends in the labium majus. The round ligaments are of little supportive value in preventing uterine prolapse but help to keep the uterus anteverted.

The uterosacral ligaments are condensations of the endopelvic fascia that arise from the sacral fascia and insert into the posteroinferior portion of the uterus at about the level of the isthmus. They provide important support for the uterus and are also significant in precluding the development of an enterocele. THE UTERUS

THE PERITONEAL FOLDS Anteriorly, the uterus is covered with peritoneum only as far down as the level of the uterine isthmus, below this the peritoneum is reflected onto the bladder, forming the uterovesical pouch. The supravaginal cervix is below this peritoneal reflection, and is only separated from the bladder by a thin layer of connective tissue. Posteriorly, the peritoneum passes downwards from the uterine body to cover the posterior surface of the supravaginal cervix and upper third of the posterior vaginal wall. This peritoneum forms the anterior boundary of the rectovaginal pouch of Douglas.

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The blood supply to the uterus arises from the uterine arteries which arise from the anterior portions of the internal iliac arteries. They also anastomose along the superior and lateral aspect of the uterus with the ovarian arteries which come down through the infundibulopelvic ligaments to the ovaries and tubes. The supply to the cervix is primarily throuth the cervical branches of the right and left uterine arteries. THE UTERUS Blood Supply

THE FALLOPIAN TUBE It is described in four parts: the interstitial portion : the segment of the tube within the wall of the uterus the isthmus : the portion of the tube has a fairly narrow lumen The medial portion of each tube is superior to the round ligament, anterior to the ovarian ligament. As the tube proceeds laterally, it is located anterior to the ovary; it then passes around the lateral portion of the ovary and partly embraces the ovary. The ampulla is the widest and longest portion fimbriae portions : the funnel-shaped opening of the tube into the peritoneal cavity, surrounded by finger-like processes. .

fluid accumulated in the pelvic cavity

hysterosalpingography

THE OVARIES The ovaries are situated on the superior surface of the broad ligament and are suspended between the ovarian ligament medially and the suspensory ligament of the ovary or infundibulopelvic ligament laterally and superiorly. They are oval, white in color, flattened organs, approximately 3 cm in length, 2 cm in depth and 1 cm in thickness. The ovaries are an important endocrine organ for the female, as well as producing her ova.

Columnar epithelium Cortex: various stages of follicles Medulla: connective tissue , fibers, smooth muscle cells, blood vessels, nerves, lymphatic vessels (1) primodial follicles ( 2) oocyte (3)nucleus of oocyte ( 4) zona pellcida (5) Corpora radiata (6) Zona granulosa (7)Follicular space (8) Theca interna (9) theca externa (10) Stroma (11) germinal epithelium

corpus luteum

THE URETER The ureter in the average female is approximately 26-28 cm in length from the renal pelvis to its entry into the bladder. Half the length is in the abdominal cavity, and half is in the pelvic cavity. The ureter passes into the pelvis very near and just superficial to the bifurcation of the common iliac artery, yet just underneath and just medial to the ovaian vessels as they travel into the pelvis through the infundibulo-pelvic ligament.

At the level of the ischial spine, the ureter passes just lateral to the uterosacral ligament, and courses obliquely just beneath the uterine artery at the side of the cervix and very near the anterolaterral fornix of the vagina. In the area, where the uterine artery across it superiorly, the ureter forms a “knee” bend and turns medially and anteriorly, and passes towards the bladder in its own “tunnel”. The ureters enter the empty bladder approximately 5 cm apart, obliquely course through the bladder wall for approximately 1.5 to 2 cm, and then enter the bladder at the corners of the trigone approximately 2.5 cm apart. THE URETER

During any pelvic surgery, whether ab-dominal, laparoscopic, or vaginal, the ureter may be injured anywhere along its travel. These areas are: at the pelvic brim just beneath the infundibulopelvic ligament; along the lateral pelvic sidewall during difficult pelvic dissections; just as the ureter passes lateral to the uterosacral ligaments; for instance, during cul-de-sac obliteration or transection of the uterosacral ligaments; as the ureter passes underneath the uterine vessels, during uterine artery ligation; or as the ureter passes just next to the anterolateral vaginal fornix during vaginal procedures. THE URETER

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