Download Lecture 22: Female Pelvic Viscera: Introduction to the Female

Lecture 22: Female Pelvic Viscera:
Introduction to the Female Internal Genital Organs:
 Hemisection
 In general, pelvic viscera are arranged in the midline, from front to back
 Value of hemisection
 Female Internal Genital Organs
 The female internal genital organs consist of the ovaries, the uterus, the uterine tubes, and the vagina
 Function
 The female internal genitalia produce sex hormones and gametes
 Like male
 In addition, the female reproductive system must be able to protect and support a developing embryo
Ovaries:
 Broad Ligament
 Background
 The ovaries, uterus, and uterine tubes are all held in position in the pelvic cavity within a common
mesentery—the broad ligament
 The broad ligament is a double-layer of peritoneum that extends from the sides of the uterus to the
floor and lateral walls of the pelvis
 Parts
 The broad ligament consists of three parts
1. The mesometrium is the largest part
 Supports uterus
2. The mesosalpinx is the superior free border
 Supports uterine tubes
3. The mesovarium is a small mesentery along the posterior aspect of the broad ligament
 Supports ovaries
 Ovary Introduction
 The ovaries—small, lumpy, almond-shaped and sized-organs—are the female gonads
 They produce the female gamete (the ovum) and reproductive hormones
 The ovaries are not covered with peritoneum, thus the ovulated egg is released into the peritoneal cavity
 Repeated ovulation gives the ovaries their scarred and distorted appearance
 Ligaments
 Two other ligaments—in addition to the broad ligament—are associated with the ovaries
 The ovarian ligament—the cranial remnant of the gubernaculum—extends from the uterus to the ovary
 The suspensory ligament is a peritoneal fold that extends from ovary to pelvic wall
 It contains the vessels and nerves of the ovary
Uterine Tubes:
 Background
 The uterine tubes/oviducts/fallopian tubes connect the ovaries to the uterus
 Each tube is ~10 cm long and ~0.7 cm in diameter
 They conduct the ovum to the uterus and are generally the site of fertilization
 In the “ideal” disposition the tubes extend laterally and arch superiorly and posteriorly above the ovaries
 Notes: In reality, in ulstrasound examination, the tubes are often asymmetrical, having varying dispositions.
 Parts
 The uterine tubes are divisible into 4 parts
1. Infundibulum
 Funnel-shaped distal end terminates with fimbriae
2. Ampulla
 Widest and longest part, and usual site of fertilization
3. Isthmus
 Part entering uterus
4. Uterine part
 Within the walls of the uterus
Uterus:
 Background
 The uterus (womb) is a thick-walled, pear-shaped, hollow muscular organ
 7.5 x 5 x 2 cm
 It is the site of development of embryo and fetus
 Anatomy
 The uterus is divided into two main regions
 The body forms the upper two-thirds
 Contains slit-like uterine cavity (~6 cm long)
 The cervix forms the lower third
 The cervix is cylindrical and ~2.5 cm long
 The body is demarcated from the cervix by the isthmus (~1 cm wide)
 Pelvic Fascia
 Introduction
 Background
 The pelvic fascia is connective tissue occupying the space between the peritoneum and the muscular
pelvic walls (where viscera is not present)
 It is a continuation of the endoabdominal (transversalis) fascia
 Pelvic Fascia Components
 The pelvic fascia is divided into two components
 Membranous pelvic fascia
 Endopelvic fascia
 Membranous Pelvic Fascia
 Background
 The membranous pelvic fascia is further subdivided into parietal and visceral parts
 The parietal pelvic fascia lines the muscles that make up the muscular walls and floor of the pelvis
 The visceral pelvic fascia directly ensheaths the pelvic organs
 Tendinous Arch
 Where the organs penetrate the pelvic floor, the parietal and visceral layer are continuous
 At this point, the parietal and visceral layers are thickened to form the tendinous arch of pelvic fascia
 The tendinous arch fastens prostate or bladder to the pubis, and prostate or vagina to the sacrum
 Endopelvic Fascia
 Background
 The endopelvic fascia varies markedly in density and content, and thus may be subdivided into two basic
parts
 Loose areolar tissue serves as “packing” material and allows the bladder and rectum to expand
 Other parts of the endopelvic fascia are condensed to form fibrous structures—the hypogastric
sheath and its laminae

Hypogastric Sheath
 The hypogastric sheath extends from the lateral wall of the pelvis and divides medially to form
ligamentous extensions, which serve as conduits for most neurovasculature—and ureters and ductus
deferentes—passing to the pelvic viscera
 As well, these extensions provide support and are thus also referred to as pelvic ligaments
 Support of the Uterus
 Background
 It is important for the uterus to remain centered in the pelvic cavity (to avoid functional disturbances to the
adjacent rectum and bladder), and resist the tendency to be pushed into the vagina (prolapse)
 This is accomplished in two main ways
 Natural position of the uterus
 Ligaments
 Natural Position
 The uterus is located posterior to the bladder and anterior to the rectum
 It is normally positioned such that the cervix is tipped forward relative to the axis of the vagina
(anteversion)
 In addition, the body of the uterus is flexed anteriorly relative to the cervix (anteflexion)
 Ligaments
 Ligamentous support of the uterus is primarily provided by the broad ligament, the cardinal (transverse
cervical) ligaments, and the uterosacral ligaments
 The round and ovarian ligaments—remnants of the gubernaculum—offer additional support
 Position of the Uterus
 Variation in Position
 Background
 The uterus is possibly the most dynamic structure in the human body
 Several factors can influence the size, proportion, and position of the uterus
 Rapid physiological changes involving the rectum and bladder
 Pregnancy
 Age
 Age
 At birth, the uterus has nearly adult proportions (length of body to length of cervix ratio of 2 to 1)
 Influence of maternal hormones
 Within weeks postpartum, the childhood ratio of 1:1 is established until puberty (2:1)
 After menopause the uterus reassumes a 1:1 ratio
 Pregnancy
 During pregnancy the uterus grows to occupy most of the abdominopelvic cavity and press against most
organs
 Compression of vena cava in supine position?
 The uterus becomes very thin-walled (nearly membranous)
 Multiparous non-gravid uterus may cause slight protrusion of abdominal wall
 Prolapse
 When intra-abdominal pressure is increased, the normally anteverted and anteflexed uterus is pressed
against the bladder
 A retroverted uterus is more likely to prolapse through the vagina


Prolapse is also more likely in the presence of a disrupted perineal body or other pelvic diaphragm
weakness
Pouches
 Peritoneum covers most of the superior and anterior parts of the uterus
 Anteriorly the peritoneum reflects off the uterus onto the bladder, while posteriorly it reflects onto
the rectum, creating pouches (vesicouterine and rectouterine)
 The rectouterine pouch, in particular, is clinically important as an area where fluid/infection can
accumulate
Vagina:
 Background
 The vagina is a distensible, musculomembranous tube, ~7-9 cm long
 It is generally collapsed, except at the cervix
 The vagina ascends posteriorly, at a 90º angle to the axis of the uterus, in-between the bladder and the rectum
 It passes between the medial margins of levator ani
 Fornices
 The vaginal fornix is the circular recess created by the protrusion of the cervix into the vagina
 The fornix is divided into anterior, posterior, and lateral fornices
 Of these, the posterior fornix is the deepest and has clinical relevance, in part due to it relation to the
rectouterine pouch
Note that in this illustration, fluid is
accumulating deep to the peritoneum, in the
rectouterine pouch. This would likely be due
to an abscess on a pelvic organ. Fluid in the
peritoneal cavity, such as blood, can also be
aspirated using this method.
Neurovasculature of Internal Genital Organs:
 Blood Supply
 Background
 Blood supply to the female internal genital organs derives from three main sources
 Ovarian artery
 Branch of lumbar aorta
 Uterine artery
 Internal pudendal artery
 Notes: The internal iliac artery has the most variable branching of any artery. Thus, identification of
branches must be done by distribution, and not pattern of branching.
 Uterus and Vagina
 Arterial blood supply to the uterus derives from the uterine artery
 Arterial blood supply to the vagina derives from two arteries
 Vaginal branch of uterine artery
 Superior and middle parts of vagina
 Vaginal and internal pudendal artery
 Middle and inferior parts of vagina
 Ovaries and Uterine Tube
 The ovaries and uterine tubes receive blood from ovarian arteries (abdominal source) and ascending
branches of uterine arteries (pelvic source)
 Both arteries bifurcate into tubal and ovarian branches
 These branches then anastamose with each other
 Venous Drainage
 The uterus and vagina drain primarily into the uterovaginal plexus of veins, which drains into the internal
iliac veins
 The uterine tubes and ovaries drain primarily into the ovarian plexus of veins, which drains into the ovarian
vein
 All four organs may drain into either plexus
 Lymphatics
 Lymph from female internal genitalia drains via two primary routes
 Most lymph drainage parallels venous drainage (internal iliac and ovarian veins) and travels to internal iliac
and lumbar nodes
 Structures located superiorly in the anterior portion of the pelvis (mainly the body of the uterus) drain to
external iliac nodes via routes that do not parallel venous drainage
 Innervation
 Somatic
 Inferior Vagina
 Only the inferior quarter of the vagina is sensitive to touch and temperature
 Somatic innervation is from deep branches of the perineal nerve
 Branch of pudendal nerve (S2-S4)
 Autonomic
 Background
 Autonomic innervation to female internal genitalia is supplied by two nerve plexuses
 Ovarian plexus
 Ovaries and uterine tubes
 Uterovaginal plexuses
 Uterus and vagina
 Sympathetic, parasympathetic, and visceral afferent fibers pass through these plexuses
 Visceral Afferents
 The ovaries and uterine tubes are intraperitoneal, thus superior to the pelvic pain line
 Pain fibers travel with sympathetic motor fibers to T11-L1
 Caudal Epidural Anesthesia
 A caudal epidural block is a popular choice for participatory childbirth
 The anesthetic agent is injected through the sacral hiatus where it bathes S2-S4 nerve roots
 Structures inferior to the pelvic pain line—birth canal, pelvic floor, perineum—are anesthetized
 Structures superior to the line—body of uterus—are not
 Mother is aware of uterine contractions