Reproductive System Week 5 Flashcards
1
Q
Describe the ovaries
A
Almond-shaped and -sized female gonads
In which the oocytes develop
Endocrine glands - produce steroid hormones
2
Q
What structure suspends the ovary?
A
The mesovarium - subdivision of the broad ligament of the uterus
3
Q
How does the structure of the ovary differ between prepubertal and postpubertal women?
A
Prepubertal - connective tissue capsule (tunica albuginea) comprising surface of the ovary is covered by smooth layer of ovarian mesothelium/surface epithelium - single layer of cuboidal cells - gives surface dull, greyish appearance - contrasts with shiny surface of adjacent peritoneal mesovarium which it is continuous with
Postpubertal - surface epithelium becomes progressively scarred and distorted - due to repeated rupture of ovarian follicles and discharge of oocytes during ovulation - scarring less in women who take oral contraceptives inhibiting ovulation
4
Q
In what structure do the ovarian vessels, lymphatics and nerves cross the pelvic brim, passing to and from the superolateral aspect of the ovary?
A
Suspensory ligament of the ovary - becomes continuous with the mesovarium
5
Q
What structure tethers the ovary to the uterus?
A
a short ‘ligament of the ovary’
6
Q
Where are the ovaries usually sitting?
A
Laterally between the uterus and the lateral pelvic wall
7
Q
What is the ligament of the ovary a remnant of?
A
The superior part of the ovarian gubernaculum of the foetus
8
Q
What structures does the ligament of the ovary connect?
A
Proximal end of ovary to lateral angle of the uterus just inferior to entrance of uterine tube
9
Q
What is the mesovarium?
A
Short peritoneal fold or mesentery - suspends the ovary
10
Q
What is the broad ligament?
A
Mesentery of the uterus
11
Q
What is the consequence of the ovary being intraperitoneal?
A
Oocyte is expelled at ovulation and passes into peritoneal cavity
But normally trapped by fimbriae of the infundibulum of the uterine tube and carried into the ampulla - may be fertilised here
12
Q
What is the function of the uterine tubes?
A
Conduct the oocytes from the peri-ovarian peritoneal cavity to the uterine cavity
Provide the usual site of fertilisation
13
Q
Where are the uterine tubes?
A
Extend laterally from the uterine horns and open into the peritoneal cavity near the ovaries
14
Q
Describe the uterine tubes
A
Extend laterally from the uterine horns and open into the peritoneal cavity near the ovaries
Approx. 10cm long
Lie in a narrow mesentery - mesosalpinx - form the free anterosuperior edges of the broad ligaments
In the ideal disposition - tubes extend symmetrically posterolaterally to the lateral pelvic walls - arch anterior and superior to the ovaries in the horizontally disposed broad ligament
In reality - tubes commonly asymmetrically arranged - one or the other often lying superior and even posterior to the uterus
15
Q
Describe the four parts of the uterine tube
A
Infundibulum - funnel-shaped distal end of the tube - opens into peritoneal cavity through abdominal ostium - finger-like processses (fimbriae) spread over medial surface of the ovary - one large fimbria is attached to the superior pole of the ovary
Ampulla - widest and longest part of the tube - begins at medial end of infundibulum - fertilisation usually occurs here
Isthmus - thick-walled part of the tube - enters the uterine horn
Uterine part - short intramural segment of the tube - passes through uterine wall - opens via uterine ostium into uterine cavity at uterine horn
16
Q
Describe the arterial supply of the ovaries and uterine tubes
A
Ovarian arteries arise from abdominal aorta - descend along posterior abdominal wall - cross over external iliac vessels at pelvic brim - enter suspensory ligaments - approach lateral aspects of ovaries and uterine tubes - terminates by bifurcating into ovarian and tubal branches - anastomoses with ovarian and tubal branches of uterine arteries - collateral circulation from abdominal and pelvic sources to both structures
Ascending branches of uterine arteries - branches of internal iliac arteries - course along lateral aspects of uterus to approach medial aspects of ovaries and tubes - terminate by bifurcating into ovarian and tubal branches - anastomoses with ovarian and tubal branches of ovarian arteries
17
Q
Describe the venous drainage of ovaries and uterine tubes
A
Veins draining ovary form pampiniform plexus of veins in broad ligament near ovary and uterine tube
Usually merge to form singular ovarian vein –> leaves lesser pelvis with ovarian artery
Right ovarian vein ascends to enter IVC
Left ovarian vein drains into left renal vein
Tubal veins drain into ovarian veins and uterine venous plexus
18
Q
Describe the innervation of the ovaries and uterine tubes
A
Derives partly from ovarian plexus (descending with ovarian vessels) and partly from uterine (pelvic) plexus
Superior to pelvic pain line because intraperitoneal –> visceral afferent pain fibres ascend retrogradely with the descending sympathetic fibres of the ovarian plexus and lumbar splanchnic nerves to cell bodies in T11-L1 spinal sensory ganglia
Visceral afferent reflex fibres follow parasympathetic fibres retrogradely through the uterine (pelvic) and inferior hypogastric plexuses and the pelvic splanchnic nerves to cell bodies in S2-4 spinal sensory ganglia
19
Q
Describe the uterus
A
Thick-walled, pear-shaped, hollow muscular organ
Embryo and foetus develop in uterus
Muscular walls adapt to the growth of the foetus and then provide the power for its expulsion during childbirth
Non-gravity uterus usually lies in lesser pelvis - body lying on urinary bladder and its cervix between the urinary bladder and rectum
Very dynamic structure - size and proportions of which change during various changes of life
20
Q
Describe the position of the uterus
A
Usually anterverted (tipped anterosuperiorly relative to axis of vagina) and anteflexed (flexed or bent anteriorly relative to the cervix- creating angle of flexion) - so that its mass lies over the bladder When the bladder is empty the uterus typically lies in a nearly transverse plane Position of the uterus changes with degree of fullness of bladder and rectum, and stage of pregnancy
21
Q
Describe the size of the uterus
A
Size varies considerably
Non-gravid uterus is approximately 7.5cm long, 5cm wide and 2cm thick
Weighs approx 90g
22
Q
Describe the two parts of the uterus
A
Body of the uterus - forms superior 2/3s - lies between layers of the broad ligament and is freely movable - 2 surfaces (vesical and intestinal)
- demarcated from cervix by the isthmus- relatively constricted segment - approx 1cm long
- fundus - rounded part - lies superior to uterine Ostia
Cervix of the uterus - cylindrical, relatively narrow inferior 1/3 of the uterus - approx 2.5cm long in an adult non-pregnant woman:
- supravaginal - between isthmus and vagina - separated from bladder anteriorly by loose connective tissue - from rectum posteriorly by recto-uterine pouch
- vaginal - protrudes into sueriormost anterior vaginal wall - rounded - surrounds external os of the uterus - surrounded by vaginal fornix
23
Q
How long is the uterine cavity?
A
6 cm in length from external os to wall of the fundus
24
Q
What are the uterine horns?
A
Superolateral regions of the uterine cavity where the uterine tubes enter
25
What does the uterine cavity continue inferiorly as?
Cervical canal - fusiform canal - extends between anatomical internal os to the external os
26
What constitutes the birth canal?
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Uterine cavity (in particular cervical canal)
Lumen of the vagina
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27
What is the birth canal?
What the foetus passes through at the end of gestation
28
Describe the three layers of the uterine wall
Perimetrium - serous coat - peritoneum supported by thin layer of connective tissue
Myometrium - middle coat of smooth muscle - greatly distended (more extensive but thinner) during pregnancy - main branches of blood vessels and nerves of uterus - contractions during childbirth are hormonally stimulated at intervals of decreasing length to dilate the cervical os and expel the foetus and placenta - during menses contractions may produce cramping
Endometrium - Inner mucous coat - firmly adhered to underlying myometrium - actively involved in menstrual cycle - differs in structure with each stage of cycle - if conceptions occurs blastocyst implants into this layer - if conception does not occur the inner surface of this coat is shed during menstruation
29
Describe the muscular tissue of the cervix compared to the uterus
Amount of muscular tissue is markedly less in cervix - mostly fibrous and is composed mainly of collagen with small amount of smooth muscle and elastin
30
Describe the ligaments of the uterus
Ligament of ovary attaches to uterus posteroinferior to uterotubal junction - vestige of ovarian gubernaculum
Round ligament of the uterus attaches anteroinferior to the uterotubal junction - vestige of ovarian gubernaculum
Broad ligament of uterus - double layer of peritoneum (mesentery) - extends from ides of the uterus to lateral walls and floor of pelvis - assists in keeping uterus in position - two layers continuous with each other at a free edge that surrounds the uterine tube - laterally the peritoneum is prolonged superiorly over the vessels as the suspensory ligament of the ovary - between layers ligaments of the ovary lie posterosuperiorly and round ligaments of uterus lie anteroinferiorly - uterine tube lies in anterosuperior free border within a small mesentery called the mesovarium on posterior aspect of broad ligament - largest part of the broad ligament is the mesometrium which serves as mesentery for the uterus itself
31
What provides dynamic support to the uterus?
Pelvic diaphragm - tone during sitting and standing and active contraction during increase itnraabdominal pressure is transmitted through the surrounding pelvic organs and the endopelvic fascia in which they are embedded
32
What provides passive support to the uterus?
It's position - anteverted and anteflexed on top of the bladder - intraabdominal pressure increase presses uterus against bladder
- cervix is least mobile part because of attached condensations of endopelvic fascia (ligaments) which may also contain smooth muscle:
- cardinal (transverse cervical) ligaments - thickening of base of broad ligament - extend from supravaginal cervix and lateral parts of the fornix of the vagina to the lateral walls of the pelvis - lateral support -
- uterosacral ligaments - pass superiorly and slightly posteriorly from the sides of the cervix to the middle of the sacrum - opposes anterior pull of round ligament - maintains anteversion - palpable in rectal examination
33
What is the consequence of dynamic and passive support of the uterus?
Prevents prolapse and disposition of uterus
34
Which of the female reproductive structures are covered by the peritoneum?
Uterus anteriorly and superiorly except for the cervix
Reflected anteriorly onto the posterior margin of the superior surface of bladder - forms the vesicouterine pouch between the bladder and uterus
and posteriorly over the posterior part of the fornix of the vagina to the rectum - rectouterine pouch
35
Describe the relations of the uterus
Anteriorly - vesicle-uterine pouch and period surface of the bladder - supravaginal part of cervix is related to the bladder - separated from it by only fibrous connective tissue
Posteriorly- recto-uterine pouch containing loops of small intestine and the anterior surface of the rectum - only the visceral pelvic fascia uniting the rectum and uterus here resists increased intraabdominal pressure
Laterally - peritoneal broad ligament flanking the uterine body and the fascial cardinal ligaments on each side of the cervix and vagina - in the transition between the two ligaments the ureters run anteriorly slightly superior to lateral part of vaginal fornix and inferior to uterine arteries - 2cm lateral to supravaginal part of cervix
36
Describe the arterial supply and venous drainage of the uterus
Uterine arteries - potential collateral supply from the ovarian arteries
Uterine veins - uterine venous plexus on each side of the cervix - drain into internal iliac veins
37
Describe the vagina
Distensible musculomembranous tube (7-9cm long)
| Extends from middle cervix of the uterus to the vaginal orifice (opening at inferior end)
38
What structures open into the vestibule of the vagina?
Vaginal orifice, external urethral orifice, ducts of the greater and lesser vestibular glands
39
What is the vestibule of the vagina?
The cleft between the labia minora
40
Where does the vaginal part of the cervix lie in the vagina?
Anteriorly in the superior vagina
41
What are the functions of the vagina?
Canal for menstrual fluid
Forms inferior part of birth canal
Receives penis and ejaculate during sexual intercourse
Communicates superiorly with cervical canal and inferiorly with the vestibule of the vagina
42
How does the vagina usually sit?
Orifice usually collapsed towards the midline so that its lateral walls are in contact on each side of an anteroposterior slit
Superior to the orifice the anterior and posterior walls are in contact on each side of a transverse potential cavity - H shaped in cross section - except at superior end where cervix holds them apart
43
Describe the relations of the vagina
Lies posterior to the fundus of the urinary bladder and urethra - projects along the midline of its inferior anterior wall
Lies anterior to anal canal, rectum, and recto-uterine pouch
Lateral to the medial margins of the levator ani (puborectalis muscles), visceral pelvic fascia and ureters
44
Describe the arterial supply and venous drainage of the vagina
Arteries
Superior vagina - derive from uterine arteries
Middle and inferior vagina - vaginal and internal pudendal arteries
Veins
Vaginal veins form vaginal venous plexuses along the sides of the vagina and within the vaginal mucosa - continuous with the uterine venous plexus as the uterovaginal venous plexus and drain into internal iliac veins through the uterine vein - also communicates with the vesical and rectal venous plexuses
45
Describe the innervation of the vagina and the uterus
Inferior 1/5 of vagina is somatic - deep perineal nerve - branch of pudendal nerve - only this part is sensitive to touch and temperature - S2-4 nerve roots - somatic afferent and motor
Superior 4/5 of vagina is visceral - uterovaginal nerve plexus - also supplies uterus - travels with uterine artery at junction of the base of the broad ligament and superior part of the transverse cervical ligament - extends to pelvic viscera from inferior hypogastric plexus and the pelvic plexus - pelvic splanchnic nerves - arising from S2-4 - parasympathetic motor fibres to uterus and vagina as well as clitoris and bulb of vestibule - visceral afferent fibres conducting pain from subperitoneal structures (cervix and vagina) - travel with parasympathetic fibres to S2-4 spinal ganglia
Sympathetic innervation - inferior thoracic spinal cord origins - pass through lumbar splanchnic nerves and intermesenteric-hypogastric-pelvic series of plexuses - visceral afferent fibres conducting pain impulses from intraperitoneal uterus - follow sympathetic innervation retrograde to inferior thoracic -superior lumbar spinal ganglia
All visceral afferent fibres from uterus and vagina not concerned with pain follow the parasympathetic route
46
What is the clinical significance of the two different routes followed by the visceral pain fibres in the female pelvis/pelvic pain line?
Offers mothers variety of types of anaesthesia for childbirth
47
What is the clinical consequence of the female genital tract communicating with the peritoneal cavity?
Infections of vagina, uterus and tubes (e.g. PID) may result in peritonitis
Inflammation of a tube (salpingitis) may result from infections that spread from the peritoneal cavity
Major cause of infertility - blockage of terrine tubes often as result of salpingitis
48
How can the patency of the uterine tubes be determined?
Hysterosalpingography - Radio graphic procedure involving injection of a water-soluble radiopaque material or CO2 gas into the uterus and tubes through the external os of the uterus - contrast medium travels through uterus and tubes - accumulation of fluid or appearance of gas bubbles in pararectal fossae region indicates that the tubes are patent
Hysteroscopy - hysteroscoped used - introduced through vagina and uterus
49
What is ligation of the uterine tubes and when is it used?
Used as surgical method of birth control
Oocytes discharged from the ovaries that enter the tubes degenerate and are soon absorbed
Done by either abdominal tubal ligation (short suprapubic incision made at pubic hair line and involves interruption - often removal of segment of tube and tubal closure by suture ligation) or laparoscopic tubal ligation (fiber optic laparoscope inserted through small incision - usually near umbilicus - apply cautery, rings or clips)
50
What factors are associated with ectopic pregnancy?
Inflammation are infection - salpingitis, PID, Pyosalpinx, adhesions
Copper IUD
Tubal ligation
Previous ectopic pregnancy
Fertility issues and use of fertility drugs
Structural concerns - surgery, adhesions
Smoking
51
Why do ectopic pregnancies usually happen?
Morula cant pass along the tube to the uterus - blastocyst may implant in mucosa of uterine tube
52
Where is a common site of ectopic pregnancy?
Uterine tubes (Ampulla particularly) 1/250 pregnancies
53
Why do ectopic pregnancies need to be diagnosed early?
May result in rupture of the uterine tube (because dont have endometrial lining) - and severe haemorrhage into the abdominopelvic cavity during first 8 weeks of gestation (arteries in close proximity)
Constitutes a threat to the mothers life and results in death of the embryo
54
What are the symptoms of a ruptured tubal pregnancy?
Iliac fossa pain - if on the right may be mistaken for appendicitis
Shoulder tip pain - if haemorrhaging
55
What are the treatments for ectopic pregnancy?
If early stages - chemotherapy drug (methotrexate) causes miscarriage
If late stages - surgery removes pregnancy along with all or part of the Fallopian tube - affects fertility
56
What is an epoophoron?
Embryonic remnant
| Forms from remnants of the mesonephric tubules of the mesonephros
57
What is a persistent duct of the epoophoron?
A remnant of the mesonephric duct that forms the ductus deferens and ejaculatory duct in the male - lies between layers of broad ligament along each side of the uterus and/or vagina
58
What is a vesicular appendage?
Remains of the cranial end of the mesonephric duct that forms the ductus epididymis - sometimes attached to the infundibulum of the uterine tube
59
What is the clinical significance of embryonic duct remnants?
Can sometimes accumulate fluid and form cysts (e.g. Gartner duct cysts)
60
What are the possible consequences of incomplete fusion of the embryonic paramesonephric ducts?
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Unicornate uterus (receives uterine duct only from one side)
Duplication in the form of bicornate uterus
Uterus didelphys (completely doubled uterus)
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61
What other positions of the uterus are possible?
Excessive anteflexion
Retro flexion
Retro version
62
Which factors increase likelihood of uterine prolapse?
Retroverted uterus
| Disrupted perineal body or atrophied pelvic floor ligaments and muscles
63
How can the uterus be examined?
Size and disposition examined by bimanual palpation
Two gloved fingers of the right hand passed superiorly in the vagina while the other hand is pressed inferoposteriorly on the pubic region of anterior abdominal wall
64
What is an early sign of pregnancy detected by bimanual palpation?
Softening of uterine isthmus - body feels separated from cervix
65
How can the uterus be further examined if vaginal exam alone doesnt reveal clear findings?
Rectovaginal examination
66
How can premalignant cervical conditions be detected?
Pap smear
Vagina distended with vaginal speculum to enable inspection of cervix
Spatula is placed in the external os of the uterus
Rotated to scrape cellular material from the mucosa of the vaginal cervix
Insertion of a cytobrush into the cervical canal that is rotated to gather cellular material from the supravaginal cervical mucosa
Cellular material is then placed on glass slides for microscopic examination
67
Where does cervical cancer spread?
Tends to spread to the bladder
May also spread by lymphogenous metastasis to external or internal iliac or sacral nodes
Haematogenous metastasis may occur via iliac veins or internal vertebral venous plexus
68
What are the four muscles that compress the vagina and act as sphincters?
Pubovaginalis
External urethral sphincter
Urethrovaginal sphincter
Bulbospongiosus
69
Which part of the vagina is particularly distensible?
Posterior fornix
70
Why do the foetus' shoulders rotate into the AP plane during shoulder delivery?
Lateral distension limited by the ischial spines - project posteromedially - and sacrospinous ligaments extending from these spines to lateral margins of sacrum and coccyx
Birth canal is therefore deep anteroposteriorly and narrow transversely at this point
71
What structures can be examined by bimanual palpation?
Cervix, ischial spines, sacral promontory
pulsations of uterine arteries through lateral fornix, ovarian cysts - through lateral parts of fornix
72
What is culdoscopy?
Endoscopic instrument (culdoscope) inserted through the posterior part of the vaginal fornix to examine the ovaries or uterine tubes - has been largely replaced by laparoscopy because provides greater flexibility for operative procedures and better visualisation of organs and less risk of bacterial contamination of peritoneal cavity
73
What is culdocentesis?
Drainage of a pelvic abscess in the recto-uterine pouch through an incision made in the posterior vaginal fornix - fluid in the peritoneal cavity can also be aspirated by this technique
74
What is laparoscopic examination of pelvic viscera particularly useful for?
Ovarian cysts
Tumours
Endometriosis
Ectopic pregnancy
75
What is endometriosis?
The presence of functioning endometrial tissue outside the uterus
76
What are the advantages and disadvantages of different anaesthetic options available for childbirth?
General - advantage - spared pain and discomfort, calm atmosphere, controlled
Disadvantage - unconscious for delivery
Regional - advantage - conscious of uterine contractions, can push to expel foetus
Disadvantage - dont experience all of the pain
Spinal (regional) - spinal subarachnoid space L3-4 level
-advantages - complete anaesthesia inferior to waist level (no pain), conscious
Disadvantage - rely on electronic monitoring of uterine contractions (cant feel it), if labour extended or level of anaesthesia inadequate difficult/impossible to readminister, severe headache (agent heavier than CSF)
Pudendal - peripheral nerve block - local anaesthesia over S2-4 dermatomes (majority of perineum and inferior vagina)
Advantages - can feel contractions (push), can be readministered but involves sharp knife in close proximity to infants head
Disadvantages - can feel contractions (pain)
Caudal epidural block - indwelling catheter in sacral canal administration - bathes S2-4 nerve roots - pain fibres from uterine cervix and superior vagina and afferent pudendal nerve fibres
Advantages - administration of more anaesthetic possible, entire birth canal, pelvic floor and majority of perineum are pain free, lower limbs not affected, aware of uterine contractions (uterine body), no spinal headache because not continuous with cranial extradural space
Disadvantages - must be administered in advance of actual delivery
77
Describe the lymphatic drainage of the female pelvic viscera
Ovaries, uterine tubes, most from fundus - right and left lumbar lymph nodes
Some vessels from the fundus (near entrance of uterine tubes and attachment of ROUND LIGAMENT) - superficial inguinal lymph nodes
Uterine body and some from cervix - pass through broad ligament - external iliac lymph nodes
Uterine cervix - along uterine vessels - in transverse cervical ligaments - internal iliac lymph nodes - along uterosacral ligaments - sacral lymph nodes
Superior vagina - internal and external iliac nodes
Middle vagina - internal iliac nodes
Inferior vagina - sacral and common iliac nodes
External orifice - superficial inguinal lymph nodes
78
What is the function of the pudendum?
Sensory and erectile tissue for sexual arousal and intercourse
Direct the flow of urine
Prevent entry of foreign material into urogenital tract
79
What is the pudendum/vulva?
The collective term for the female external genitalia
80
What is the mons pubis?
Rounded, fatty eminence anterior to the pubic symphysis, pubic tubercles and superior pubic rami
Formed by a mass of fatty subcutaneous tissue
Amount of fat increases at puberty, decreases after menopause
Continuous surface with anterior abdominal wall
Covered in pubic hair after puberty
81
What are the labia majora?
Prominent folds of skin that indirectly protect the clitoris and urethral and vaginal orifices
Each largely filled with a finger like digital process of loose subcutaneous tissue containing smooth muscle and termination of round ligament of uterus
Passes inferoposteriorly from mons pubis toward the anus
Lie on the sides of a central depression (pudendal cleft) within which are the labia minora and vestibule
External aspects in adult covered with pigmented skin containing many sebaceous glands and pubic hair
Internal aspects are smooth, pink and hairless
Thicker anteriorly where join to form the anterior commissary
Posteriorly in nulliparous women merge to form posterior commissary - overlies perineal body and is posterior limit of the vulva - usually disappears after first vaginal birth
82
What are the labia minora?
Rounded folds of fat-free, hairless skin
Enclosed in the pudendal cleft
Immediately surround and close over the vestibule of vagina (where external urethral and vaginal orifice open)
Core of spongy connective tissue - contains erectile tissue at their age and many small blood vessels
Anteriorly form two laminae
Medial laminae of each side unite as the frenulum of the clitoris
Lateral laminae unite anterior to the glans clitoris - forming the prepuce of the clitoris
Young women/virgins - labia minora connected posteriorly by small transverse fold - frenulum of labia minora
Internal surface of each consists of thin moist skin, has pink colour of mucous membranes and contains many sebaceous glands and sensory nerve endings
83
What is the clitoris?
An erectile organ located where the labia minora meet anteriorly
Consists of a root and a small, cylindrical body
which are composed of two crura, two corpora cavernosa and the glans clitoris
Courage attach to inferior pubic rami and perineal membrane, deep to labia
Body covered by prepuce
Together body and glans are approximately 2cm in length and <1cm diameter
Clitoris is not functionally related to urethra and urination
Solely organ of sexual arousal
Highly sensitive, enlarges on tactile stimulation
Glans clitoris is most highly innervated part of clitoris - densely supplied with sensory endings
84
What is the vestibule of the vagina?
The space surrounded by labia minora into which orifices of the urethra and vagina and ducts of the greater and lesser vestibular glands open
External urethral orifice located 2-3cm posteroinferior-inferior to the glans clitoris and anterior to vaginal orifice
Openings of the duct of the paraurethral glands on either side of urethral orifice
Openings of the ducts of greater vestibular glands - upper, medial aspects of labia minora - 5 and 7 o'clock positions relative to vaginal orifice in lithotomy position
Hymen - thin anular fold of mucus membrane - partially or wholly occludes the vaginal orifice - only hymenal caruncles visible after rupture - demarcate the vagina from the vestibule - hymen considered primarily developmental vestige
85
Why are the condition of the frenulum of labia minora and hymen important legally?
Can provide critical evidence in cases of child abuse and rape
86
What are the bulbs of the vestibule?
Paired masses of elongated erectile tissue - 3cm in length
Lie along side of vaginal orifice, superior or deep to the labia minora, immediately inferior to perineal membrane
Covered inferiorly and laterally by bulbospongiosus muscles extending along their length
Homologous with bulb of the penis
87
What re the vestibular glands (Bartholin glands)?
Greater vestibular gland - 0.5cm diameter - superficial perineal pouch - lie on each side of vestibule of vagina - posterolateral to vaginal orifice and inferior to perineal membrane - in superficial perineal pouch - round or oval - partly overlapped posteriorly by bulbs of the vestibule - partially surrounded by bulbospongiosus muscles - slender ducts pass deep to bulbs and open into vestibule on each side of vaginal orifice - secrete mucus into vestibule during sexual arousal
Lesser - small glands on each side of vestibule - open into it between urethral and vaginal orifices - secrete mucus into vestibule which moistens the labia and vestibule
88
Describe arterial supply of the vulva
External pudednal and internal pudendal arteries
Internal pudendal artery supplies most of skin, external genitalia and perineal muscles - labial branches and clitoris branches
89
Describe the venous drainage of the vulva
Labial veins tributaries of internal pudendal veins and accompanying veins of internal pudendal artery
Venous engorgement during excitement phase of sexual response - increase in size and consistency of clitoris and bulbs of vestibule of the vagina
90
Describe the innervation of the vulva
Anterior aspect - derivatives of lumbar plexus - anterior labial nerves - from ilioinguinal nerve and the genital branch of genitofemoral nerve
Posterior aspect- derivatives of sacral plexus - perineal branch of posterior cutaneous nerve of thigh laterally - pudendal nerve centrally (primary nerve of perineum) - posterior labial nerves supply labia - deep and muscular branches of perineal nerve supply orifice of vagina and superficial perineal muscles - dorsal nerve of clitoris supplies deep perineal muscles and sensation to the clitoris
Bulb of vestibule and erectile bodies of clitoris receive parasympathetic fibres via cavernous nerves from uterovaginal nerve plexus - produces vaginal secretion, erection of clitoris, engorgement of erectile tissue inthe bulbs of the vestibule
91
Describe the lymphatic drainage of female perineum
Skin (incl anoderm), inferiormost vagina, vaginal orifice, vestibule - superficial inguinal nodes
Clitoris, vestibular bulb, anterior labia minora - deep inguinal lymph nodes or direct to internal iliac nodes
Urethra - internal iliac or sacral nodes
92
Describe the perineal muscles of the female
Superficial perineal muscles :
Superficial transverse perineal - origin internal surface of ischiopubic ramus and ischial tuberosity - passes along inferior aspect of posterior border of perineal membrane to perineal body - muscular branch of perineal nerve - supports and fixes perineal body/pelvic floor to support abdominopelvic viscera and resist increased intraabdominal pressure
Ischiocavernous - origin internal surface of ischiopubic ramus and ischial tuberosity - embraces crus of clitoris, inserting onto inferior and medial aspects of crus and to perineal membrane medial to crus - muscular branch of perineal nerve - maintains erection of clitoris by compressing outflow veins and pushing blood from root into body
Bulbospongiosus - origin perineal body - inserts into pubic arch and fascia of corpora cavernosa of clitoris - muscular branch of perineal nerve - supports and fixes perineal body/pelvic floor - sphincter of vagina - assists in erection of clitoris and bulb of vestibule - compresses greater vestibular gland
93
Describe pathologies of the greater vestibular glands
Site of origin of most vulvar adenocarcinomas
Bartholinitis - inflammation - palpable when infected (enlarge to 4-5cm)- impinge on wall of rectum - occlusion of vestibular gland duct can predispose
Bartholin gland cyst - occlusion of vestibular gland without infection - accumulation of mucin
94
Why should women practice Kegel exercises?
Superficial transverse perineal, bulbospongiosus and external anal sphincter muscles in women commonly underdeveloped - when developed contribute to support of pelvic viscera and help prevent urinary stress incontinence and postpartum prolapse of pelvis viscera
In learning to contract and relax the musculature - women able to relax them during uterine contractions - less obstructed passage for foetus and decreasing likelihood of tearing perineal muscles
95
What is the clinical consequence of disruption of the perineal body?
PErineal body - important structure - final support of the pelvic viscera - linking muscles that extend across the pelvic outlet - like crossing beams supporting the overlying pelvic diaphragm
Stretching or tearing attachments of perineal muscles from perineal body can occur during childbirth - removing support from pelvic floor
Prolapse of pelvic viscera - including prolapse of uterus and or vagina may occur
Can also be disrupted by trauma, inflammatory disease, infection - can result in formation of fistula connected to the vestibule
Attenuation of the perineal body associated with separation of the puborectalis and pubococcygeus parts of levator ani - formation of cystocoele, rectocoele, or enterocoele - hernial protrusions of part of the bladder, rectum, or rectovaginal pouch (respectively) into vaginal wall
96
What is an episiotomy and why is it used?
During vaginal surgery and labour - surgical incision of the perineum and inferoposterior vaginal wall - to enlarge vaginal orifice - intention of decreasing excessive traumatic tearing of perineum and uncontrolled jagged tears of the perineal muscles
When descent of foetus is arrested or protracted, when instrumentation is necessary, or to expedite delivery in signs of foetal distress
Prophylactic episiotomy is widely debated and declining in frequency
Mediolateral - lower incidence of severe laceration than median episiotomy - less likely to be associated with damage to anal sphincters and canal
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What is the pelvic floor?
A muscular and fibrous tissue diaphragm
Which fills the lower part of the pelvic canal
Closes the abdominal cavity
Defines the upper border of the perineum
Supports the pelvic organs
Pierced by the urethra, vagina and rectum at the urogenital hiatus - at rest held closed by the tone of the muscles
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Which muscles make up the levator ani?
Puborectalis - thicker, narrower, medial part - continuous between posterior aspects of bodies of right and left pubic bones - u-shaped sling (puborectal sling) - passes posterior to anorectal junction, bounding urogenital hiatus - major role in faecal continence
Pubococcygeus - thinner, but wider intermediate muscle - arises lateral to puborectalis from posterior aspect of body of pubis and anterior tendinous arch - passes posteriorly in nearly horizontal plane - lateral fibres attach to the coccyx and medial fibres merge with the contralateral muscle to form a tendinous plate - part of the anococcygeal body (ligament between anus and coccyx) - shorter muscle fibres extend medially and blend with fascia around midline structures - named for th structure near their termination e.g. Pubovaginalis
Iliococcygeus - posterolateral part of levator ani - arises from posterior tendinous arch and ischial spine - thin and often poorly developed (aponeurotic rather than muscular) - blends with anococcygeal body posteriorly
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What structures make up the antero-inferior pelvic wall?
Primarily bodies and rami of the pubic bones and pubic symphysis
More of a weight-bearing floor in anatomical position - supports weight of urinary bladder
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What structures make up the lateral pelvic wall?
Right and left hip bones - each including obturator foramen closed by obturator membrane
Obturator interns muscles cover and pad most of the lateral walls
These muscle fibres converge posteriorly, become tendinous, turn sharply to pass through lesser sciatic foramen and attach to greater trochanter of femur
Medial surfaces of these muscles covered by obturator fascia - thickened centrally as tendinous arch which provides attachment for the pelvic diaphragm
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Describe the structures that make up the posterior wall, posterolateral walls and roof of the pelvis
In anatomical position posterior wall consists of bony wall and roof in midline - sacrum and coccyx
Musculoligamentous posterolateral walls - ligaments associated with sacroiliac joints (sacro-iliac, sacrospinous and sacrotuberous ligaments) and piriformis muscles (arise from superior sacrum, pass laterally leaving the lesser pelvis through the greater sciatic foramen to attach to greater trochanter of femur - -occupy most of the greater sciatic foramen)
The nerves of the sacral plexus are immediately anteromedial (deep) to the piriformis muscles
Gap at lower border of piriformis allows passage of neurovascular structures between pelvis, perineum and lower limb (gluteal region)
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Describe the structures that form the pelvic floor
The bowl or funnel-shaped pelvic diaphragm - consisting of coccygeus and levator ani muscles and fascias covering the superior and inferior aspects of these muscles - lies in lesser pelvis - separates pelvic cavity from perineum (roof of perineum)
Diaphragm attaches to obturator fascia, dividing the muscle into a pelvic and perineal portion - medial to pelvic portions are the obturator nerves and vessels and other branches of internal iliac vessels
Coccygeus muscles - arise from lateral aspect of inferior sacrum and coccyx - lie on and attach to deep surface of sacrospinous ligament
Levator ani - larger and more important part of pelvic floor - attached to the bodies of the pubic bones anteriorly, ischial spines posteriorly, and to thickening in obturator fascia (tendinous arch of levator ani) between the two bony sites on each side
An anterior gap between the medial borders of the levator muscles of each side - urogenital hiatus - gives passage to the urethra and vagina in females
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Describe the tone of levator ani in different situations
Normally - tonically contracted - support abdominopelvic viscera and to assist in maintaining urinary and faecal continence
Actively contracted during forced expiration, coughing, sneezing, vomiting and fixation of the trunk during strong movement of upper limbs (e.g. Heavy lifting) to increase support for viscera and contribute to increased pressure
Tonic contraction of puborectalis bends the anorectum anteriorly - active contraction is important in maintaining faecal continence immediately after rectal filling or during peristalsis when the rectum is full and the involuntary sphincter is inhibited
Levator ani must relax and consequently descend to allow urination and defecation
Increased intra-abdominal pressure for defecation provided by contraction of thoracic diaphragm and muscles of anterolateral abdominal wall
Following urination and defecation all parts of levator ani contract to elevate the pelvic floor back to the resting position
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What is the perineum?
Shallow compartment bounded by the pelvic outlet and separated from the pelvic cavity by the fascia covering the inferior aspect of the pelvic diaphragm (levator ani and coccygeus muscles)
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What is the perineal region?
Narrow region between the proximal parts of the thighs
When lower limbs abducted it is a diamond-shaped area extending from the mons pubis anteriorly in females, medial surfaces of thighs laterally and gluteal folds and superior end of the intergluteal cleft posteriorly
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What are the boundaries of the perineum?
Pubic symphysis - anteriorly
Ischiopubic rami - anterolaterally
Ischial tuberosities - laterally
Sacrotuberous ligaments - posterolaterally
Inferiormost sacrum and coccyx - posteriorly
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How can the perineum be divided?
Transverse line joining the anterior ends of the ischial tuberosities divides the perineum into two triangles - oblique planes intersect at the transverse line:
Anal triangle - posterior to the line - anal canal and its orifice, anus, surrounded by ischioanal fat
Urogenital triangle - anterior to the line - closed by a thin sheet of tough, deep fascia (perineal membrane), stretches between the two sides of the pubic arch covering the anterior part of the pelvic outlet (fills the gap in the pelvic diaphragm /urogenital hiatus) - perforated by urethra in both sexes and vagina in females - provides foundation for erectile bodies of the external genitalia - superficial features of the triangle
Midpoint of the line joining the two triangles - central point of the perineum - location of the perineal body - irregular mass, variable in size and consistency and containing collagenous and elastic fibres, and both skeletal and smooth muscle - lies deep to the skin with relatively little overlying subcutaneous tissue, posterior to vestibule of vagina or bulb of penis and anterior to anus and anal canal
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What is the perineal body?
An irregular mass, variable in size and consistency
Contains collagenous and elastic fibres, both skeletal and smooth muscle
Lies deep to the skin - relatively little overlying subcutaneous tissue
Posterior to vestibule of vagina or bulb of penis and anterior to the anus and anal canal
Site of convergence and interlacing of fibres of several muscles:
Bulbospongiosus, external anal sphincter, superficial and deep transverse perineal muscles and smooth and voluntary slips of muscle from the external urethral sphincter, levator ani and muscular coats of the rectum
Anteriorly blends with posterior border of the perineal membrane and superiorly with the rectovesical or rectovaginal septum
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Describe the perineal fascia
Consists of superficial and deep layers
Subcutaneous tissue consists of a superficial fatty layer and a deep membranous layer (perineal fascia)
In females the fatty layer makes up the substance of the labia majora and mons pubis and is continuous anteriorly and superiorly with the fatty layer of subcutaneous tissue of the abdomen (camper fascia) - in males this layer is greatly diminished in the urogenital triangle being replaced by smooth dartos muscle in the penis and scrotum but it is continuous between the penis or scrotum and thighs with the fatty layer of the abdomen - in both sexes it is continuous with the ischioanal fat pad in the anal region
The membranous perineal fascia does not extend into the anal triangle, being attached posteriorly to the posterior margin of the perineal membrane and perineal body - laterally attached to fascia lata of the superiormost medial aspect fo the thigh - anteriorly in males continuous with the dartos fascia of penis and scrotum - on each side of and anterior to the scrotum it becomes continuous with the membranous layer of subcutaneous tissue of the abdomen (scarpa fascia) - in females the perineal fascia passes superior tot eh fatty layer forming the labia majora and becomes continuous with the scarpa fascia of the abdomen
The deep perineal fascia (investing fascia) intimately invests the ischiocavernosus, bulbospongiosus and superficial transverse perineal muscles - attached laterally to the ischiopubic rami - anteriorly fused to the suspensory ligament of the penis/ clitoris and continuous with deep fascia covering external oblique of abdomen and rectus sheath
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What is the superficial perineal pouch?
Potential space between the perineal fascia and perineal membrane, bounded laterally by the ischiopubic rami
In males contains:
Root of penis and ichiocavernosus and bulbospongiosus
Proximal (bulbous) part of spongey urethra
Superficial transverse perineal muscles
Deep perineal branches of internal pudendal vessels and nerves
Females contains:
Clitoris and ischiocavernosus
Bulbs of vestibule and surrounding muscle (bulbospongiosus)
Greater vestibular glands
Superficial transverse perineal muscles
Related vessels and nerves (deep perineal branches of the internal pudendal vessels and nerves)
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What is the deep perineal pouch?
Bounded inferiorly by the perineal membrane, superiorly by the inferior fascia of the pelvic diaphragm and laterally by the obturator fascia - include the fat-filled anterior recesses of the ischio-anal fossae, the superior boundary in the region of the urogenital hiatus is indistinct
In both sexes contains:
Part of urethra, centrally
Inferior part of the external urethral sphincter muscle, above the centre of the perineal membrane, surrounding the urethra
Anterior extensions of ischioanal fat pads
Males:
Intermediate part of urethra
Deep transverse perineal muscles - on superior surface of perineal membrane, trasnversely along posterior aspect
Bulbourethral glands - embedded in deep perineal muscle
Dorsal neurovascular structures of the penis
Females:
Proximal urethra
Mass of smooth muscle in the place of the deep transverse perineal muscles on posterior edge of the perineal membrane - associated with perineal body
Dorsal neurovasculature of clitoris
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What is the current concept of the external urethral sphincter?
In the female the posterior edge of the perineal membrane is typically occupied by a mass of smooth muscle in the place of the deep transverse perineal muscles
Immediately superior to the posterior half of the perineal membrane the deep transverse perineal muscle (typically only in males) offers dynamic support to the pelvic viscera
The urethral sphincter muscle is not a flat, planar structure
The superior fascia is the intrinsic fascia of the external urethral sphincter muscle as opposed to a urogenital diaphragm with a superior and inferior fascia
The inferior fascia of the pelvic diaphragm is considered to be the superior boundary of the deep pouch as opposed to the superior fascia of the "UG diaphragm"
The male external urethral sphincter is more like a tube or trough than a disc - only the inferior part of the muscle forms an encircling investment (true sphincter) for the intermediate part of the urethra inferior to the prostate - this includes loop-like portions (compressor urethral) - larger trough-like part extends vertically to the neck of the bladder as part of the isthmus of the prostate, displacing the glandular tissue and investing the protastatic urethra anteriorly and anterolaterally only
Female - external urethral sphincter is more properly a urogenital sphincter - a part forms a true anular sphincter around the urethra - several additional parts extend from it - superior part extends to neck of bladder, subdivision extends inferolaterally to ischial ramus on each side(compressor urethral muscle) and yet another band-like part encircles both the vagina and the urethra (uethrovaginal sphincter)
In both males and females the external urethral sphincter muscles are oriented perpendicular to the perineal membrane rather than lying parallel to it
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Where does urine collect if the urethra ruptures below the perineal membrane?
Superficial perineal pouch
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What are the ischioanal fossae?
Fossae on each side of the anal canal - large fascia-lined, wedge-shaped spaces between the skin of the anal region and the pelvic diaphragm
Apex of each fossa lies superiorly where the levator ani muscle arises from the obturator fascia
Wide inferiorly, narrow superiorly
Filled with fat and loose connective tissue
Communicate by means of the deep postanal space over the anococcygeal ligament (body)
Boundaries:
Lateral - ischium and obturator internus + fascia
Medial - external anal sphincter, levator ani
Posterior - sacrotuberous ligament and glute maximus
Anterior - bodies of pubic bones inferior to puborectalis, extend into the UG triangle superior to the perineal membrane (anterior recesses of the ischio-anal fossae)
Each filled with fat body of the ischio anal fossa - support the anal canal but they are readily displaced to permit descent and expansion of the anal canal - traversed by tough fibrous bands as well as several neurovascular structures (inferior anal vessels and nerves and S2 and S3 cutaneous and the perineal branch of S4)
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Describe the clinical consequences of rupturing of the urethra in males
Fractures of the pelvic girdle - especially those resulting from separation of pubic symphysis and puboprostatic ligaments --> rupture of intermediate part of urethra --> extravasation of urina and blood into the deep perineal pouch --> may pass superiorly through the urogenital hiatus and distribute extraperitoneally around the prostate and bladder
Common site of rupture of spongy urethra and extravasation of urine is int he bulb of the penis - results from forceful blow to perineum or from incorrect passage of a transurethral catheter
Rupture of the corpus spongiosum and spongy urethra results in urine passing from it into the superficial perineal space - may pass into the loose connective tissue in the scrotum, penis, and deep to the membranous layer in the inferior abdominal wall
Urine cannot pass far into the thighs because the membranous layer of superficial perineal fascia blends with the fascia lata jsut distal to the inguinal ligament
Urine cannot pass posteriorly into the anal triangle due to blending of the superficial and deep perineal fascia around the superficial perineal muscles and with the posterior edge of the perineal membrane between them
Rupture of a blood vessel would produce similar results
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Why do you see rectal prolapse in starvation?
Fat bodies of the ischio-anal fossae are the last reserves of fatty tissue to disappear with starvation - lack of support so rectal prolapse relatively common
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Why is the pectinate line clinically important?
Approximates the level of visceral to parietal/somatic transition
Affects such things as the types of tumours that occur and the direction in which they metastasise
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How does infection occur in the ischio-anal fossae, what are the signs and symptoms and what are the common consequences?
May result in the formation of ischioanal abscesses - painful
Infection can occur :
- after cryptitis - inflammation of an anal sinus
- extension from a pelvirectal abscess
- after a tear in the anal mucous membrane
- from a penetrating wound in the anal region
Diagnostic signs of abscess:
Fullness and tenderness between the anus and ischial tuberosity
Peri-anal abscess may rupture spontaneously - opening into anal canal, rectum or perianal skin
An abscess in one fossa may spread to the next through the deep postanal space - can form a horseshoe shaped abscess around the posterior anal canal
Chronically constipated persons - anal valves and mucosa may be torn by hard faeces - anal fissure usually located in posterior midline inferior to anal valves - painful because supplied by inferior rectal nerves
Peri-anal abscessmay follow infection of an anal fissure and spread to ischioanal fossa or pelvis to form abscesses there
Anal fistula may result from the spread of an anal infection a nd cryptitis - one end opens into the anal canal and the other end opens into an abscess in the ischioanal fossa or peri-anal skin
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What are internal haemorrhoids ?
Piles
Prolapse of rectal mucosa (anal cushions) containing the normally dilated veins of the internal rectal venous plexus
Result from a breakdown of the muscularis mucosae
Those that prolapse into or through the anal canal often compressed by the contracted sphincters, impeding blood flow --> strangulate and ulcerated - presence of abundant ateriovenous anastamoses --> blood bright red if bleed - current practice is to treat only prolapsed, ulcerated internal haemorrhoids
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What are external haemorrhoids?
Thrombosis in the veins of the external rectal venous plexus - covered by skin
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What are some predisposing factors for haemorrhoids?
Pregnancy, chronic constipation and prolonged toilet sitting and straining, and any disorder that impedes venous return (intraabdominal pressure increase etc.)
The veins of the rectal plexuses normally appear varicose but increased in portal hypertension
Internal haemorrhoids occur most commonly in the absence of portal hypertension
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How are haemorrhoids treated?
Internal haemorrhoids are not painful and can be treated without anaesthesia (above pectinate line )
External haemorrhoids can be painful but often resolve in a few days
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How does traumatic childbirth lead to anorectal incontinence?
Stretching of the pudendal nerves --> pudendal nerve damage
