Lecture 6 - Female pelvis and perineum Flashcards
What organs can be found in the female pelvic cavity?
- Ovaries and fallopian tubes
- Uterus and cervix
- Vagina
- Ureters, bladder and urethra
- Rectum
- Caecum, appendix, parts of the sigmoid colon and ileum (false pelvis)
- Vessels, nerves and lymphatics
What is different about the male and female pelvic cavity?
No sharing of the reproductive and urinary passages in females as in the male.
How is the uterus joined to the posterior pelvic wall?
Via the broad ligaments - they are transverse mesenteries.
What are the landmarks of the true pelvis?
- Bound in front and below by pubic symphysis and superior rami of the pubis
- Above and behind by sacrum and coccyx
- Laterally by broad, smooth quadrangular area of bone
Where do the fallopian tubes join the uterus?
At the joining of the funds and the body of the uterus.
Where does fertilisation of the egg normally take place?
In the ampulla region of the fallopian tubes, which is then pushed through into the uterus via vibrations of the infundibulum.
What muscle is the uterus made up of?
Smooth involuntary muscle.
How are the cervix and vaginal wall stabilised?
Via cervical ligaments, which anchor the cervix in position within the pelvis and prevent the uterus from prolapsing through the vagina by providing pass support.
What are the cervical ligaments?
- Pubo-cervical ligament
- Transverse cervical/cardinal ligament
- Uterosacral ligament
Which is the most important cervical ligament?
Transverse cervical ligament - strongest and most important ligament that holds the cervix and vaginal wall in place despite the abdominal pressure pushing them downwards.
What is the cervix?
A fibro-muscular cylinder that is roughly 2.5cm long from the internal and external os. It opens between the body of the uterus and the outside via the vagina.
How can premature birth be linked to the cervix?
If the cervix is shorter than 2.5cm, premature birth is common.
What cells make up the cervical canal?
The cervical canal is lined with mucus-secreting simple columnar epithelium.
What is the vaginal surface of the cervix made up of?
Stratified squamous non-keratinised epithelium. There are no glands in the vagina.
Describe the relationship between the cervix and the vagina?
- Projects into the anterior vaginal wall at a right angle to the vaginal axis
- Cervix and vagina form an angle of roughly 90 degrees, known as the angle of anteversion
- The cervix is anteverted onto the vagina
- The body of the uterus is ante flexed on the cervix
What do the cervical ligaments form part of?
The pelvic fascia.
What is the vagina?
A fibromuscular canal that is typically between 7 and 9 cm long.
Where is the urethra (female) found?
Fused to the anterior vaginal wall - herniation through to the vagina can occur if the wall is weak.
Why is the posterior fornix clinically relevant?
- Can be used as a route to the ovaries such as in IVF treatment allowing collection of eggs from the ovary
- Can also drain a pelvic abscess through the posterior fornix as fluid commonly collects here in the rectal-uterine pouch, preventing damage of other organs
What are the different regions of the uterus?
- Fundus
- Body
- Lower segment
- Cervix
What are the different regions of the fallopian tubes?
- Infundibulum
- Ampulla
- Isthmus
- Fimbriae
- Uterine parts
What is the role of the fimbriae and the infundibulum?
They are involved in the collection of the ovum from the ovary after ovulation. The egg will enter the fallopian tube here at the abdominal ostium.
How is there potential communication between the abdominal cavity and the reproductive organs in the female?
Via the abdominal ostium at the end of the fallopian tube - there is no such passage in males.
What happens after the 9th month of pregnancy?
The head of the foetus descends into the true pelvis and engages, causing the uterus to move inferiorly slightly. In late pregnancy it can be difficult to breathe due to diaphragmatic movements against the growing foetus.
What structures can be palpated from the vaginal wall?
- Cervix
- Ischial spine (runs closely to the pudendal nerve)
- Sacral promontory
- Uterine artery pulse
- Ovary
What is the sacral promontory?
The inwardly-projecting anterior part of the body of the first sacral vertebra.
How is the wall of the pelvis supplied with blood?
Sacral, gluteal and obturator branches.
Where does the pudendal artery supply?
The perineum and recto-anal region via the inferior rectal branch.
What are the main branches of arteries supplying the pelvic viscera?
- Superior vesical
- Uterine
- Middle rectal
How is blood supplied to the uterus?
Via the uterine artery - enlarges during pregnancy.
Describe the pathway of the uterine artery.
- Branch off of the abdominal aorta
- Runs medially towards the cervix
- Crosses the ureter about 1cm from the cervix
- Ascending branch supplies the uterine tubes and the ovary (as well as the ovarian artery)
- Descending branch supplies the vagina
Where does the ovarian artery branch off from?
Upper abdominal aorta
What is a common mistake made in hysterectomies?
The ureters can accidentally be tied off with the uterine arteries.
What is the role of the perineal body?
Lots of important ligaments and muscles in the pelvic cavity are anchored here.
What are the contents of the female perineum?
- Vulva (external genitalia)
- Mons pubis
- Labia majora and minora
- Clitoris
- Vestibule of the vagina
- Vestibular bulbs and glands
What are the two vestibular glands called?
- Greater vestibular gland (Bartholin’s)
- Lesser vestibular gland (Skene’s)
What is the hymen?
Thin mucosal fold that is normally perforated at the centre. Following intercourse and childbirth, the hymen is torn and only a few tags remain.
Where do the sympathetic nerves to the pelvis form a plexus?
Hypogastric plexus anterior to the bifurcation of the abdominal aorta (L4).
Where does the abdominal aorta typically bifurcate?
L4
Where do pelvic organs drain their lymph to?
- Mainly to the external and internal iliac nodes that are found around the arteries
- Testis and ovaries drain into para-aortic nodes
- Perineum and external genitalia drain into superficial inguinal nodes (subcutaneous below inguinal ligament)
