Human Anatomy PDF - Pelvis (Lab 3)

HUMAN ANATOMY PART III PELVIS BY Jerzy Gielecki M.D, Ph.D Anna Żurada M.D, Ph.D Lab. session 3 Viscera of the female pelvis 1. THE FEMALE INTERNAL GENITAL ORGAN...................................... 1.1. The uterus.........................................................................................

HUMAN ANATOMY PART III PELVIS BY Jerzy Gielecki M.D, Ph.D Anna Żurada M.D, Ph.D Lab. session 3 Viscera of the female pelvis 1. THE FEMALE INTERNAL GENITAL ORGAN...................................... 1.1. The uterus........................................................................................................... 1.2. Arterial supply of the uterus............................................................................ 1.3. Venous drainage of the uterus.......................................................................... 1.4. Lymphatic drainage of the uterus.................................................................... 1.5. The uterine tubes............................................................................................... 1.6. Arterial supply of the uterine tube.................................................................. 1.7. Venous drainage of the uterine tube................................................................ 1.8. Lymphatic drainage of the uterine tube.......................................................... 1.9. Innervation of the uterine tube........................................................................ 1.10. The ovaries....................................................................................................... 1.11. Arterial supply of the ovaries........................................................................ 1.12. Venous drainage of the ovary........................................................................ 1.13. Lymphatic drainage of the ovary.................................................................. 1.14. The vagina....................................................................................................... 2. THE FEMALE EXTERNAL GENITAL ORGANS................................... 2.1. The mons pubis.................................................................................................. J. St. Gielecki and A. Żurada -HUMAN ANATOMY Copyright © 2019 MedRadEd 44 2.2. The labia majora................................................................................................ 2.3. The labia minora................................................................................................ 2.4. The vestibule of the vagina............................................................................... 2.5. The clitoris.......................................................................................................... 2.6. The bulbs of the vestibule................................................................................. 2.7. Arterial supply of the female external genital organs................................... 2.8. Venous drainage of the female external genital organs................................. 2.9. Lymph drainage of the female external genital organs................................. 2.10. Innervation of the female external genital organs...................................... J. St. Gielecki and A. Żurada -HUMAN ANATOMY Copyright © 2019 MedRadEd 45 1. The female internal genital organ 1.1. The uterus The uterus (uterus) is a thick (2-3 cm), pear shaped muscular female reproductive organ, measuring about 7-8 cm in length, 4-5 cm in width, which occupies the central region of the true pelvis. The uterus is divided into four regions: a. the fundus (fundus), superior, rounded part of the uterus or the part located above the entrance of the uterine tubes. The regions where the entrances of the paired uterine tubes are located are called cornua of the uterus, b. the body (corpus), the region between fundus and isthmus, superior two thirds of the organ, c. the isthmus (isthmus), a 1 cm constricted region between the body and the cervix, d. the cervix (cervix), is a 2 cm long region, half of which penetrates the posterior region of the vagina, which is called the infravaginal part. In opposition to that, the supravaginal part of cervix is defined as a region between the isthmus and posterior vaginal wall. The cavity of the uterus is triangular in shape. The cervical canal appears as a spindle-shaped channel which narrows, anteriorly at the ostium, and posteriorly at the isthmus. The uterine ostium is a small aperture at the vaginal end of the cervical canal. Sacrum represented in pieces 1 Plane of brim of pelvis 2 3 Uterus Peritoneum 4 1/3 Anterior abdominal wall 1/3 Bladder Pubic symphysis 1/3 Urethra Spincter urethrae Vagina Levator ani muscle 5 Coccyx Rectum Anal canal Fig. 3.1. Midsagittal section through the female pelvis. J. St. Gielecki and A. Żurada -HUMAN ANATOMY Copyright © 2019 MedRadEd 46 The supporting components of the uterus are as follows: a. the cardinal ligament or the transverse cervical ligament (ligamentum cardinale uteri) is important for stabilization of the cervix in the midline position. It extends from the lateral pelvic wall to the cervix of the uterus and lateral side of the vagina, b. the uterosacral ligament (ligamentum sacrouterinum) - runs posteriorly from sides of the cervix, around sides of the rectum, to the middle part of the sacrum, c. the round ligament (ligamentum teres uteri) - passes under the anterior layer of the broad ligament, from the point of the organ, which is located anteroinferiorly to the entrance of the uterine tube, to the deep inguinal ring, d. the broad ligament (ligamentum latum), double layer fold of the peritoneum - extends from the lateral sides of the uterus to the floor and lateral walls of the pelvis. It contains the uterine artery, extraperitoneal tissue (parametrium), ovarian artery and vein, venous plexus. The round ligaments and uterine tubes are enclosed between layers of the broad ligament. It also gives an attachment for the ovaries as double-layer mesovarium and for the uterine tubes as mesosalpinx, e. the suspensory ligaments of the ovary (ligamentum suspensorium ovarii), fold of the peritoneum, which is prolongation of the broad ligament; it passes from the lateral end of the ovary to the lateral pelvic wall, f. the vesicouterinal ligament (ligamentum vesicouterinum) extends from the anterior surface of the cervix to the fundus of the urinary bladder, h. the pelvic diaphragm or the pelvic floor consists of all muscles, which form the diaphragm and are important for supporting the uterus. Umbilical Artery Obturator nerve artery vein Mesosalpinx Meso-ovarium Ligament of the ovary Suspensory ligament of the ovary Ovary Obturator internus muscle Vagina Ureter Mesometrium Levator ani muscle J. St. Gielecki and A. Żurada -HUMAN ANATOMY Copyright © 2019 MedRadEd 47 Fig. 3.2. Folds of the peritoneum around the female reproductive organs. The uterus has the following relations: a. Anteriorly the body of uterus relates to the vesicouterine pouch (excavatio vesicouterina) of peritoneum (peritoneum is reflected from the posterior margin of the superior surface of the urinary bladder into the fundus of the uterus), which separates the bladder from the uterus. This region of the bladder also relates to the supra vaginal region of the cervix. The vaginal cervix is related to the anterior and lateral fornices of the vagina. b. Posteriorly the body of uterus comes in contact with the peritoneal lining of the rectouterine pouch /of Douglas/ (excavatio rectouterina), and coils of ileum or sigmoid colon. The peritoneum, which is reflected from the fundus into the ampulla of the rectum, separates the uterus from the rectum. c. Laterally, the body of uterus is related to the broad ligament and uterine vessels. The supravaginal region of the cervix contacts laterally with the descending ureters, which cross inferiorly to the uterine artery 2 cm from the cervix. The uterus has a vesical and an intestinal surface. The relations of the uterus vary with the amount of urine in the bladder and feces in the rectum. Normally, the organ is inclined anteriorly over an empty bladder. In addition, the uterus displays two angular displacements: an angulation between its body and its cervix (anteflexion, anteflexio), and a larger angle (90 to 110o) with the vagina (anteversion, anteversio). The wall of the uterus consists of three layers: a. the outer layer (perimetrium), which is formed by the parietal peritoneum with the connective tissue, b. the middle layer (myometrium), which is the muscular part of the uterine wall. It is a layer of smooth muscles, which normally is about 15 mm thin and increases about 100 times in length during pregnancy, c. the inner layer (endometrium). It is a mucosus coat, which is sloughed off during each menstrual cycle. 1.2. Arterial supply of the uterus The main artery of the uterus is the uterine artery (arteria uterina), which is a branch from the internal iliac artery. It arises as the third branch from the internal iliac artery and runs medially between layers of the broad ligament. The uterine artery is divided into three parts: a. the first portion - descends medially and anteriorly, b. the second portion - passes horizontally, superiorly to the ureter, which crosses that part 2 cm laterally from the cervix of the uterus. This part gives off a branch, which supplies the cervix of the vagina, c. the third portion - ascends along lateral side of the body of the uterus and gives off many branches to the uterus. At the end, it turns laterally just below the entrance of the J. St. Gielecki and A. Żurada -HUMAN ANATOMY Copyright © 2019 MedRadEd 48 uterine tube and runs along the uterine tube to the ovary and anastomoses (unites) with the ovarian artery. 1.3. Venous drainage of the uterus The uterine vein (vena uterina) accompanies adequate artery and drains to the internal iliac vein. The veins of the uterus form the uterine venous plexus (plexus venosus uterinus), which is located on each side of the cervix, and is connected freely with the rectal, vesical and vaginal plexuses. The uterine venous plexus drains into the internal iliac vien through the uterine vein. 1.4. Lymphatic drainage of the uterus The lymph from the uterus drains in four main directions:  the lymph from the fundus is drained into the superficial inguinal lymphatic nodes (nodi lymphatici inguinales superficiales) through lymphatic vessels going with the round ligament,  also from the fundus and superior part of the body lymph passes through lymphatic vessels within the suspensory ligament of the ovary to the lumbal lymphatic nodes (nodi lymphatici lumbales), J. St. Gielecki and A. Żurada -HUMAN ANATOMY Copyright © 2019 MedRadEd 49  the lymph from the inferior part of the body passes to the external iliac lymph nodes (nodi lymphatici iliaci externi),  the lymph from the cervix is returned to the sacral and internal iliac lymph nodes (nodi lymphatici sacrels et iliaci). Fundus of uterus Intramural part of tube Isthmus of tube Ampulla of tube Infundibulum of tube Body of uterus Cervix of uterus Isthmus of uterus Fimbriae Vagina Fig. 3.3. Female internal genital organs. 1.5. The uterine tubes The paired uterine tubes - Fallopian tubes (tuba uterina s. oviductus) are located on the left and right upper borders of the broad ligament and extend laterally from the cornua of the uterus. They end freely in the peritoneal cavity not so far from the ovaries. The main function of the Fallopian tube is transport of the oocytes from the ovary (the ova is directed by the ciliated epithelium of the tube to the uterine cavity) and sperm from uterus to the ampulla, where fertilization usually takes place. The portion of the broad ligament adjacent to the tube is known as the mesosalpinx (mesosalpinx). Each (10 cm long, 1 cm width) tube is divided into four parts: a. the infundibulum, resembling the mouth of a trumpet, represents the expanded lateral projection, by which the tube communicates with the peritoneal cavity. The rim of this structure has a multitude of finger-like projections, the fimbriae (20-30 of them), which overlie the ovary, b. the ampulla, the widest part of the uterine tube, connects the infundibulum to the isthmus, c. the isthmus, is the narrowest part (2,5 cm long) by which the tube connects to the superolateral uterine wall, J. St. Gielecki and A. Żurada -HUMAN ANATOMY Copyright © 2019 MedRadEd 50 d. the intramural part, is shortest segment, which passes through muscular part of the uteral wall and terminates at the aperture of the uterine ostium, by which the tube connects to the cavity of uterus. 1.6. Arterial supply of the uterine tube The tubal branches come from two opposite directions. The tubal branch from the uterine artery passes laterally and anastomises with another tubal branch from the ovarian artery. 1.7. Venous drainage of the uterine tube Veins of the Fallopian tube drain into the uterine (trough the uterine plexus) and ovarian veins. 1.8. Lymphatic drainage of the uterine tube The lymph vessels drain along the ovarian artery and vein into the lumbal lymph nodes. 1.9. Innervation of the uterine tube It receives sympathetic fibres from the coeliac plexus (upper part of the tubal plexus) and from the inferior hypogastric plexus. The uterine tube receives parasympathetic fibres from the 10th cranial nerve (nervus vagus) and splanchnic pelvic nerves. 1.10. The ovaries The ovaries (4 by 2 cm, weighing 2 - 4 g, oval in shape) are bilateral primary sex female organs, which occupy the right and left ovarian fossa (fossa ovarica dextra et sinistra) of the lateral pelvic wall. Each ovary (ovarium) is covered by cuboidal epithelium, which blends with the peritoneal lining of the mesovarium, however the oocytes are expelled during ovulation into the peritoneal cavity. Each ovary has: a. anterior margin (margo anterior s. mesoovaricus) with hilum of the ovary (hilus ovarii) and mesovarium (mesoovarian border of the ovary), b. posterior margin (margo posterior), which is free, J. St. Gielecki and A. Żurada -HUMAN ANATOMY Copyright © 2019 MedRadEd 51 c. inferior end - uteral end, (extremitas inferior), d. superior end - tubal end (extremitas superior), e. medial surface (facies medialis), f. lateral surface (facies lateralis). The ovary is supported by: a. The mesovarium (mesovarium) is an attachment to the posterior border of the broad ligament. b. The suspensory ligaments of the ovary (ligamentum suspensorium ovarii) is an additional attachment, which is the lateral prolongation of the broad ligament. It provides the ovarian vessels and nerves, which enter to the hilum of the ovary through the mesovarium. c. The ligament of the ovary (ligamentum ovarii proprium) extends from the lateral angle of the uterus to the uteral end of the ovary. It contains the ovarian branch from the uterine artery. Relations of the ovary. The ovary is located within the ovarian fossa of the lateral pelvic wall, which is a shallow depression within the parietal peritoneum. It is situated below the terminal line of the pelvis and in front to the sacroiliac joint. The ovarian fossa is bounded by medial umbilcal ligament in front and by the ureter and internal iliac artery. Superiorly, the ovarian fossa is bounded by the external iliac vessels. Sectioned ovary may be divided into: a. outer layer - cortex - contains most of the ovarian follicules b. inner layer - medulla - composed of hormonally functional stroma Follicules and corpora lutea may enlarge the ovary to the diameter of 6 cm without being thought to be pathologically distended. 1.11. Arterial supply of the ovaries The ovary is supplied by the ovarian arteries (arteriae ovaricae), which arise from the abdominal aorta just below the origin of the renal arteries, descend to the pelvic brim, cross superiorly the external iliac arteries, next pass within the suspensory ligaments of the ovary and enter the ovary through the hilum. In addition, the ovary is supplied by the ovarian branch of the uterine artery (ramus tubarius arteriae uterinae). It runs from the uterine artery laterally within the ligament of the ovary and anastomoses with the ovarian artery. 1.12. Venous drainage of the ovary J. St. Gielecki and A. Żurada -HUMAN ANATOMY Copyright © 2019 MedRadEd 52 The ovarian vein leaves the hilum and forms the pampiniform plexus (plexus pampiniformis) near the ovary, between the layers of the broad ligament. On both sides the ovarian veins ascend from the pampiniform plexuses. The right ovarian vein (vena ovarica dextra) enters to the IVC, but the left ovarian vein (vena ovarica sinistra) joins the left renal vein 1.13. Lymphatic drainage of the ovary Lymph vessels follow blood vessels through the suspensory ligaments of the ovary and return lymph to the lumbal lymph nodes (nodi lymphatici lumbales). 1.14. The vagina The vagina (vagina) is female organ of copulation. It is a distensible muscular tube (7 to 9 cm in length) which extends between vestibule of the vagina and uterus. The organ consists of two walls which are in contact except at their upper end. The posterior vaginal wall (12 cm long) is slightly longer than the anterior wall (9 cm long). The vagina descends anteroinferiorly. It pierces the urogenital diaphragm together with the sphincter uretrae muscle. Assuming the bladder is empty, the posterior portion of the vagina receives the neck of the uterus at an angle of about 900. This angle increases as the bladder fills and elevates the fundus of the uterus. In cross sectional anatomy the lower part of the organ resembles an exaggerated letter H with a long horizontal bar limited by two short parallel lines. Only in the superior end where the cervix of the uterus enters the vagina, anterior and posterior walls are not in apposition. The vaginal recess around the cervix is called the fornix. The relations of the organ are as follows: a. anteriorly: bladder, terminal parts of the ureters and urethra, b. posteriorly: recto-vaginal pouch (space), rectum and anal canal, c. laterally: broad ligament and ureter, levator ani mm, d. inferiorly: perineal body, vestibule of the vagina. External orifice of the vagina is sourrounded by the sphincter of the vaginal muscle. 2. The female external genital organs 2.1. The mons pubis The mons pubis (mons pubis) is a fatty elevation anterior to the pubic symphysis, which is covered by pubic hairs. J. St. Gielecki and A. Żurada -HUMAN ANATOMY Copyright © 2019 MedRadEd 53 2.2. The labia majora The labia majora (labia maiora pudendi) are two folds of skin, which contain large amount of fatty tissue, situated on each side of the pudendal cleft. They meet posteriorly at the posterior labial commissure (commissura labiorum posterior) and anteriorly at the anterior labial commissure (commissura labiorum anterior). They are embryologically homologous to the male scrotum. 2.3. The labia minora The labia minora (labia minora pudendi) are delicate folds, which are located between the labia majora and they border the vestibule of the vagina. The labia minora join together superiorly to the clitoris at the prepuce of the clitoris (preputium clitoridis) and posteriorly in young female they meet at the frenulum of the labia minora, which is incised during labour (episiotomy). J. St. Gielecki and A. Żurada -HUMAN ANATOMY Copyright © 2019 MedRadEd 54 2.4. The vestibule of the vagina The vestibule of the vagina (vestibulum vaginae) is a space bounded laterally by the labia minora anteriorly by frenulum of the clitoris (frenulum clitoridis), posteriorly by the frenulum of the labia minora (frenulum labiorum pudendi). There opens the external urethral orifice, about 2.5 cm below the clitoris and anteriorly to the vaginal orifice. The vaginal orifice (ostium vaginae) is closed by the hymen during childhood and may be only a few cm in diameter in virgins. 2.5. The clitoris The clitoris (clitoris) is 2 -3 cm long, and is an organ corresponding in female to the penis in male. It is located posteriorly to the anterior labial comissure and anteriorly to the prepuce of the clitoris. The clitoris consists of: root, body (composed of by two crura and two corpora cavernosa), glans. The clitoris enlarges during tactile stimulation, but not significantly. 2.6. The bulbs of the vestibule Each bulb of the vestibule (2.5 cm) is covered by the corresponding bulbospongiosus muscle and its fascia. The bulb of the vestibule (bulbus vestibuli) is composed of erectile tissue and is situated on both sides of the vaginal orifice. The posterior end of the bulb (male) is penetrated by the urethra which crosses the length of the corpus spongiosum as the spongy urethra to open at the glans penis. The (female) urethra opens independently between vagina and clitoris without passing through erectile tissue of the corpus spongiosum. The posterior ends of each bulb of the vestibule are in contact with a small (0.5 cm) nodular mass formed by the greater vestibular gland. The bulbs of the vestibule and the greater vestibular glands are located deep to the labia minora. a. Greater vestibular glands The greater vestibular gland - Bartholin's gland, (glandula vestibuli major) is about 0,5 cm in diameter, round in shape and secretes lubricating mucus into the vestibule of the vagina. b. Lesser vestibular glands The lesser vestibular glands (glandulae vestibuli minores) are small glands which also produce mucous and open into the vestibule of the vagina. J. St. Gielecki and A. Żurada -HUMAN ANATOMY Copyright © 2019 MedRadEd 55 2.7. Arterial supply of the female external genital organs Arterial supply of the vulva is generally from the two pudendal arteries: a. the external pudendal artery (arteria pudenda externa),which gives off the following branches:  the dorsal artery of the clitoris (arteria dorsalis clitoridis),  the deep artery of the clitoris (arteria profunda clitoridis),  the posterior labial arteries (arteriae labiales posteriores),  the artery of the vestibule bulb (arteria bulbi vestibuli). b. the internal pudendal artery (arteria pudenda interna):  the anterior labial arteries (arteriae labiales anteriores). 2.8. Venous drainage of the female external genital organs All the veins from the vulva drain into the internal pudendal vein (vena pudenda interna) and next into the internal iliac vein except two external pudendal veins (venae pudendae externae) – they receive blood from the anterior labial veins and return blood to the femoral vein. 2.9. Lymph drainage of the female external genital organs Most of lymph vessels drain into the superficial inguinal lymph nodes (nodi lymphatici inguinales superficiales) and deep inguinal lymph nodes (nodi lymphatici inguinales profundi). 2.10. Innervation of the female external genital organs The nerves of the vulva are branches from the ilioinguinal nerve (nervus ilioinguinalis), the genital branch of the genitofemoral nerve (ramus genitalis nervi genitofemoralis) and pudendal nerve (nervus pudendus). J. St. Gielecki and A. Żurada -HUMAN ANATOMY Copyright © 2019 MedRadEd 56