O&G Clinical Anatomy Flashcards
What are the functions of the bony pelvis?
- Support of the upper body when sitting and standing
- Transference of weight from the vertebral column to the femurs to allow standing and walking
- Attachment for muscles of locomotion and abdominal wall
- Attachment for external genitalia
- Protection of pelvic organs, their blood & nerve supplies, their venous and lymphatic drainage
- Passage for childbirth
What makes up the bony pelvis?
2 hip bones, sacrum, coccyx
Which 3 bones make up the hip bones?
Ilium, ischium and pubis
- Label these parts of if the bony pelvis
*
What is the name of the angle formed by the pubic arch?
Sub-pubic angle
*What forms the pelvic inlet?
sacral promontory, ilium, superior pubic ramus and pubic symphysis
*What forms the pelvic outlet?
Pubic symphysis, ischiopubic ramus, ischial tuberosities, sacrotuberous ligaments and coccyx
*What is the pelvic cavity situated between?
Pelvic inlet and pelvic floor
Which pelvic structure is used to measure gestation in pregnancy?
Pubic symphysis
Which pelvic structures can be used to determine stations during birth, and = station 0?
Ischial spines
What kind of joint is the pubic symphysis?
Secondary cartilaginous (secondary cartilaginous often occur in the midline)
What kind of joint is the sacroiliac joint?
Generally synovial anteriorly, fibrous posteriorly
What are the 2 ligaments of the pelvis that dont cross or stabilise joints, but prevent vertical displacement of the sacrum when weight suddenly moves vertically e..g jumping or late pregnancy?
Sacrotuberous and sacrospinous ligaments
What are the 2 ligaments of the pelvis that dont cross or stabilise joints, but prevent vertical displacement of the sacrum when weight suddenly moves vertically e..g jumping or late pregnancy?
Sacrotuberous and sacrospinous ligaments. (They also form the greater and lesser sciatic foramina)
What is the attachment of the sacrotubrous and sacrospinous ligaments, and which is most posterior?
Sacrotuberous: sacrum + coccyx to ischial tuberosity
Sacrospinous: sacrum + coccyx to ischial spine (this is the most posterior)
What arteries, veins and nerves are at risk of damage in pelvic fractures?
Common iliac artery and common iliac vein, and sacral plexus
What are the main differences between the male and female pelvis?
- AB and transverse diameter of the inlet and outlet are wider in females
- Sub-pubic angle is wider
- Pelvic cavity is shallower in female
- Sacral promontory is larger in males, making pelvic inlet heart shaped
- Acetabulum is more medial in females, and wider
What is the name of the space between foetal cranial bones?
Fontanelles
*Vertex
Diamond shaped area of the skull between the parietal eminence and anterior + posterior fontanelles
Movement of one bone over another to allow the foetal head to pass through the pelvis during labour, aided by sutures and fontanelles
Moulding
In what direction should the foetus be facing when it enters the pelvic cavity and why?
Transverse direction (to the right or left) because the occipitofrontal diameter of the foetus’ head is larger than the biparietal diameter, which matches the mums pelvis which is wider transversely than it is AP
How should the baby’s head position change when descending through the pelvic cavity, and then exiting the cavity?
It should rotate and end up in a flexed position, and then leaving the cavity in an extended occipitoanterior position (occiput facing up, and face down). Once the baby is delivered there is further rotation to the the shoulders and the rest of the baby can be delivered.
What borders do the inferior part of parietal peritoneum form?
Floor of peritoneal cavity and roof over pelvic organs
Where would any excess fluid in the upright female collect, and how is this drained?
Recto-uterine pouch (Pouch of Douglas). This is drained via needle through the posterior fornix of the cavity
What are the two pouched formed by the peritoneum in the female?
Vesico-uterine, and recto-uterine (Pouch of Douglas)
What is the pouch formed by the peritoneum in the male?
Recto-vesical
What is the broad ligament and what is its function?
Double layer of peritoneum, helps maintain the uterus in it correct midline position
What is the round ligament, and where does it attach?
An embryological remnant which passes through the deep inguinal ring to attach to the superficial tissue of the female perineum
What holds the uterus in position, and what can occur if these are weak?
Number of strong ligaments e.g. uteroscaral, endopelvic fascia and pelvic floor muscles. Weakness of these can result in prolapse
What are the 3 layers of the body of the uterus?
Perimetrium, myometrium and endometrium
*What is the most common position of uterus?
Anteverted and ante flexed
What is a normal variation of uterine position?
Retroverted and retroflexed
What junction must be sampled in a smear test?
Squamo columnar junction
What is the risk with the uterine tubes opening into the peritoneal cavity?
Infection could pass between the two areas, e.g. PID, or ectopic pregnancy
True or False: the walls of the vagina are normally collapsed and in contact
True, except superiorly where the cervix holds them apart forming a fornix
What are the 4 parts of the cervical fornix?
Anterior, posterior and 2 lateral
How is the position of the uterus palpated during digital examination?
Using bimanual palpation through posterior fornix
How is the position of the adnexae (uterine tubes and ovaries) palpated during digital examination?
Bimanual palpation through lateral fornices and over iliac fossa with the other hand (normally non-palpable)
Where is the perineum located?
Between the pelvic diaphragm (pelvic floor mostly) and the skin
When is the pelvic floor contracted?
Trick question! It is tonically contracted all of the time, but contracts further reflexively in situations of increased intra-abdominal pressure