Anatomy of the female pelvis Flashcards
What is the pelvic inlet?
The pelvic brim, the entrance into the true pelvis - bound by the pubis, the iliopectineal lines, the ala and the promontory of the sacrum
What is the pelvic outlet?
The pelvic outlet extends from lower border of pubic symphysis to the tip of the cocyx- bound by the pubic arch, sacrotuberous ligaments, ischial tuberosities and the tip of the coccyx
What type of joint is the pubic symphysis?
secondary cartilaginous joint
What are the three muscles that make up the levator ani muscle?
Iliococcygeus
pubococcygeus
puborectalis muscle
What is the purpose of the levator ani muscle?
supports mid vagina, urethra and rectum
helps to fix the perineal body in place
assists anal and vaginal sphincters
What are the four muscles making up the pelvic floor?
(first three make up levator ani)
iliococcygeus
pubococcygeus
puborectalis
and
coccygeus muscle
Where is the perineal membrane in the pelvis?
the perineal membrane sits just below the deep perineal pouch
What does the deep perineal pouch contian?
the external urethral sphincter (very important) the compressor urethrae, the opening for the vagina, and the deep transverse perineal muscles
What is the most superficial layer of the pelvic floor?
the perineal muscles- these sit below the perineal membrane
what are the perineal muscles?
The ischiocavernosus
bulbospongiosus muscle
and the
superficial transverse perineal muscle
What is the perineal body (aka perineum) and why is it important?
The perineal body is the ‘zipper ‘ for the muscles of the pelvic floor
it has attachments to 8 muslces
What could potentially cause damage to the perineal body?
may be damaged due to trauma, repeated stretching from births, accidents or inaccurate episiotomy
- damage to this area may result in incontinence of the anus, urethral incontinence, or prolapse of pelvic organs (uterus and bladder)
What is an episiotomy? What are the arguments for/against it?
An episiotomy is an incision in the perineal body at the time of delivery
- the argument for episiotomy is that it prevents a perineal tear or excess strechign of the muscle. It may protect the fetus if the delivery is slow or the child is in distress - it may also prevent damage if abnormal presentation
- argument against is that natural ‘tearing’ may be better during childbirth
- there is no real indication about which method is better- the cut is ALWAYS MADE POSTEROLATERALLY
What is the superficial perineal pouch?
This is the most superficial pouch of the pelvis and it contains the tissues that form the clitoris, and three muscles – the ischiocavernosus, bulbospongiosus and superficial transverse perineal muscles. The greater vestibular glands (Bartholin’s glands) are also located in the superficial perineal pouch.
How long is the vagina? What are its relations to other organs? what cell type is it lined with?
The vagina is 7-10 cm long, it is lined with squamous epithelium.
anterior to the vagina is the bladder, posterior is the rectum, laterally is the ovarian artery and ureters
What are the vaginal fornices?
They are the gutters surrounding the cervis - anteror, 2xlateral, posterior
What can we palpate from the lateral fornices?
if you go through the posterior fornix, where would you be?
lateral fornices you can palpate the ureter and the uterine artery through (uterine artery more anterior)
just behind the posterior fornix is the pouch of douglas
during inproper abortions, what is a real risk associated with the posterior fornix?
one may rupture the posterior fornix and enter the pouch of douglas which is intraperitoneal - therefore a person may develop peritonitis
What is the pouch anterior to the uterus? What is the pouch posterior to the uterus?
anterior = uterovesica pouch
posterior = pouch of douglas
does the peritoneum wrap around the uterus?
no, the peritoneum passes over the uterus and the bladder - which is why you can give catheters suprapubically
What is the round ligament of the uterus a remnant of?
The round ligament of the uterus is a remnant of the gubernaculum and passes through the inguinal canal
Where is the bulbospongiosus muscle?
in the superficial perineal pouch just around the bartholin’s glands
Describe the histology of the Uterus
body and fundus composed of thick muscular walls = myometrium- this muscle is hormone sensitive and undergoes hypertrophy and hyperplasia during pregnancy - it can also develop fibroids
The endometrium = basal layer is composed of the spongiosum and compactum - these develop over the menstrual cycle and shed with a period
Describe the cervix
lower 1/3 of the uterus
supravaginal and vaginal parts
during pregnancy it holds the fetus in the uterus - dilates during labor to allow delivery
provides alkaline secretion for sperm penetration
mainly fibroelastic tissue
in a non - pregnant woman, it is firm
in a pregnant woman it is soft in consistency
