Part 15: Female Internal Genital Organs and Urethra Flashcards
What is the size and shape of the uterus?
Pear shape
8x5x3cm (3x2x1 inches)
What are the parts to the uterus?
Fundus: Part above entrance of tubes, 5cm side to side, 3cm thick.
Body: Tapers down from fundus and flattened in AP plane
Cervix: Tapers below body and protrudes into vagina
What is the canal of cervix?
Continuous with cavity of body of uterus. Via internal os, passes to vagina then via external os. Circular in nulliparous women, slit like after child birth
What is the structure of uterus?
Parts of uterus covered by peritoneum or perimetrium
Bulk is myometrium which consists of 3 ill defined muscle layers (outer-longitudinal, deep-circular)
Endometrium: the mucous membrane. Lined with columnar epithelium, dips into endometrial stroma to form glands. Thickness changes with cycle.
Where does the epithelium of endometrium change to that of vagina?
Cervix - just inside external os, changes to stratified squamous epithelium. These are mucous secreting with glands.
What is the blood supply of the uterus?
Via uterine artery - branch of IIA via broad ligament, also supplies cervix and vagina and anastomoses with ovarian artery along tubes
What is the venous drainage of the uterus?
Veins form plexus across pelvic floor, communicate with veiscal and rectal plexuses and drains to internal iliacs
What is the lymph drainage of the uterus?
Mainly to external iliac nodes, some also reaches inguinal nodes via round ligament and inguinal canal
What is the nerve supply of the uterus?
Branches of pelvic plexus
Sympathetic provides vasoconstrictor, possible motor effect. Pain runs in sympathetic nerves back to T10-L1 - thus block must be this high during labour.
Mainly hormonal influence.
How does the uterus develop?
Fusion of paramesonephric ducts to form uterus and upper vagina. Incomplete fusion results in a median septum
What position is the uterus normally found?
80% anteverted
20% retroverted
How does uterus maintain its position?
Most fixed part is cervix - via attachments to bladder and vagina - assisted by pelvic diaphragm, pelvic fascia pubvaginalis and perineal body.
The round ligament important as it keeps uterus forward tilting from attachments at cervix.
Describe the broad ligament?
Lax double fold of peritoneum lying laterally between side wall of uterus and pelvis. Posterior layer has ureter adhering to it. Lateral attachment crosses obturator nerve, superior vesical and obturator artery. Upper border has free edge, contains uterine tube (mesosalpinx)
Lateral quarter forms suspensory ligament of ovary
Anterior border is bulged forward by round ligament
Where does the round ligament lie?
From uterus/tube junction to DIR then to labium majus. largely visceral muscle. Lies in anterior part of broad ligament, continuous with ovarian ligament (Remnants of gubernaculum)
What is the lateral ligament?
Also known as cardinal ligament, lateral cervical or Mackenrodt’s ligament.
Thickenings of connective tissue from base of each broad ligament from cervix to vagina, then laterally to side wall of pelvis
Where does the ureter run in relation to uterus?
Pass about 1-2cm lateral then in front of cervix/vagina fornix
Where are the uterosacral ligaments?
Condensation of broad ligament, extend backwards from cervix, embracing rectouterine pouch and becoming attached to fascia over piriformis. Keep cervix braced backwards against pull of round ligaments to help maintain anteversion
What are the 4 parts of the uterine tubes?
Intramural - proximal 1cm embedded in uterine wall
Isthmus - upper edge of broad ligament, straight and narrow
Ampulla - dilates
Infundibulum - trumpet like expansion to terminate with fimbriations
What is the structure of uterine tubes?
2 layers of visceral muscle (inner circular, outer longitudinal).
Mucous membrane thrown into folds which increases towards ampulla. Surface epithelium is mixture of ciliated and non-ciliated columnar epithelium.
What is the blood supply of the uterine tubes?
Blood supply is largely from tubal branch of ovarian artery - this anastomoses with uterine artery close to uterus.
Where are the ovaries positioned?
Embedded in posterior leaf of broad ligament, attached to a mesovarium. Side wall of pelvis in angle between EIA and IIA on obturator nerve
Is ovary invested in peritoneum?
No - attached via mesovarium but not covered
What ligaments support ovary?
Ovarian ligament to uterus (continuation of round ligament - gubernaculum)
Suspensory ligament - thickening of broad liagement
What is ovarian blood supply?
Via ovarian artery - branch of aorta, runs down via suspensory ligament
What is the venous drainage of ovary?
Form plexus in mesovarium (pampiniform plexus) - R drains to IVC, L to L renal
What is the nervous supply of ovaries?
Sympathetic fibres from aortic plexus, parasympathetic from inferior hypogastric plexus
What is the structure of the ovary?
Fibrous stroma covered by layer of cubical cells to make epithelium.
Multiple follicles.
Where does the ovary develop from?
Paramesonephric ridge - starts in posterior abdominal wall and migrates down gubernaculum
What is the length of vagina and direction?
10cm, same direction as pelvic brim, transverse lumen.
What are the vaginal fornix?
Space where cervix protrudes into vagina.
Anterior, posterior, lateral. Ureter is adjacent to lateral fornix then passes forwards to anterior fornix before reaching bladder
What is the blood supply of the vagina?
Vaginal branch of IIA (+ uterine, inferior vesical, middle rectal)
What is the lymph drainage of the vagina?
Drains to EIN and IIN with lower parts draining to superficial inguinal nodes
What is the structure of the vagina?
Muscular layer of smooth muscle lined internally by mucous membrane and covered externally by fibrous tissue
There is no muscularis mucosa and no glands
What is the development of the vagina?
Upper part formed from the distal part of the mesonephric duct, lower part from the urogenital sinus, with the labia formed from the urogenital folds
How long is the female urethra, what is its course?
4cm long
all except upper most part is embedded into anterior wall of vagina. Exits 2.5cm behind clitoris
Does the female urethra have internal sphincter?
No
What is blood supply to urethra?
inferior vesical and uterine arteries
What is the lymph drainage of urethra
Mainly to the IIN (+ EIN)
What is the nerve supply to urethra?
Inferior hypogastric plexus and perineal nerve
What is the structure of the urethra?
Longitudinal layers of visceral muscle with mucous membrane lined with transitional epithelium with scattered mucous glands. Outside visceral muscle is the external urethral sphincter which is circular skeletal muscle and thickest near middle of urethra
What are the paraurethral glands of skene?
Large mucous glands of urethra, female homologue of prostate and open via 2 ducts just inside external meatus
