5 Anatomy of the Female Pelvis and Partuition

Question 1

What makes up the pelvic inlet?

Answer 1

sacral promontory
margin of ala
linea terminalis
superior pubic symphysis

Question 2

What comprises the pelvic outlet?

Answer 2

pubic symphysis
ischiopubic rami
ischial tuberosity
sacrotuberous ligament
coccyx

Question 3

Which of the pelvic inlet or outlet is bigger?

Answer 3

the pelvic outlet is smaller

Question 4

how can the parietal bone move?

Answer 4

they can move on top of each other, elongating the skull

Question 5

What can be measured on MRI pelvimetry?

Answer 5

sagittal pelvic inlet diameter
transverse inlet diameter
bispinous outlet
sagittal pelvic outlet

Question 6

What is the smallest diameter in the pelvis, what is the significance of this?

Answer 6

bispinous outlet (10.5)

child can arrest here

Question 7

What is the shape of the pelvic inlet?

Answer 7

wide transverse and narrower AP diameter

Question 8

What is the shape of the pelvic outlet?

Answer 8

narrow transverse and wide AP diameter

Question 9

What are the front and back of the foetal skull referred to as?

Answer 9

occiput

sinciput

Question 10

What is the widest part of the foetal skull?

Answer 10

biparietal diameter at 9.5cm

Question 11

What are the 3 layers to the uterine wall?

Answer 11

endometrium
myometrium
perimetrium

Question 12

What are the layers of the myometrium?

Answer 12

internal muscle
middle muscle (thick, spiral arrangement)
external muscle (longitudinal)

Question 13

Going down, what are the parts of the uterus?

Answer 13

fundus
corpus
anatomical internal os
isthmus
histological internal os
cervix

Question 14

What is the difference in composition of the fundus compared to the cervix?

Answer 14

fundus is 90% muscle

cervix is 10% and hence much more collagenous

Question 15

What happens to the uterine wall over pregnancy?

Answer 15

first 20 weeks - hypertrophy of muscle wall

next 20 weeks - distension, decrease in thickness

Question 16

How does the weight of the uterus change over pregnancy?

Answer 16

50g to 950g

Question 17

What is the height of the uterus at 12 weeks?

Answer 17

pubic symphysis

Question 18

What is the height of the uterus at 20 weeks?

Answer 18

umbilicus

Question 19

What is the height of the uterus at 36 weeks?

Answer 19

xiphisternum

Question 20

What is significant about uterus size at 24 weeks?

Answer 20

from this point onwards, the accurate gestational age estimate can be taken

Question 21

What is aortocaval compression?

how can this be avoided?

Answer 21

reduction in venous return to the heart

women are advised to sleep on their left to avoid this

Question 22

What is Potters’ syndrome?

Answer 22

in some chemical kidey diseases causing impaired urine production, the uterus can be smaller

Question 23

What arteries are associated with female genitalia?

Answer 23

ovarian artery, which anasotmoses with the uterine artery

vaginal artery

Question 24

What is significant about the structure of the uterine artery?

Answer 24

tortuous path to allow for expansion

Question 25

What are the 3 main phases of childbirth?

Answer 25

dilation of cervix expulsion of foetus afterbirth of placenta

Question 26

What facilitates dilation of the cervix?

Answer 26

relaxin

Question 27

What is the cranial position when the cervix dilates?

Answer 27

normally right or left occipitotransverse

Question 28

What is the state of the histological internal os at 36 weeks?

Answer 28

full of mucous

Question 29

What are the phases of foetus expulsion?

Answer 29

``` engagement descent flexion medial rotation extension lateral rotation expulsion ```

Question 30

What happens in engagement?

Answer 30

biparietal diameter enters pelvic inlet

Question 31

What happens in descent?

Answer 31

head goes through pelvic cavity

Question 32

What happens in flexion?

Answer 32

neck flexes | head forced anteriorly under force of contraction

Question 33

What happens in medial rotation?

Answer 33

the baby changes from lateral facing to occipitoanterior position, via a wave of uterine contraction

Question 34

What happens in extension?

Answer 34

head extends around the pubic symphysis

Question 35

What happens in lateral rotation?

Answer 35

face turns laterally, so the anterior shoulder can expel and then the posterior shoulder

Question 36

When does labour technically start?

Answer 36

when the mucous of the histological internal os is no more

Question 37

How is haemorrhage avoided in placenta delivery?

Answer 37

rapid involusion of the fetus disrupts the plaenta ad tears the blood vessels, fibres the pinch off the arterioles

Question 38

What is a 3rd degree pelvic tear?

Answer 38

tearing the rectal sphincter

Question 39

What is a 4th degree pelvic tear?

Answer 39

tearing of the rectal sphincter with rectal mucosa involvement

Question 40

What nerve can be damaged during childbirth?

Answer 40

the pudendal nerve

Question 41

What is the function of an episotomy?

Answer 41

prevention of tears progressing to 3rd or 4th degree and vaginal prolapse

Question 42

Name 2 types of episotomy

Answer 42

midline episotomy | mediolateral episotomy

Question 43

What do you have to do if a woman presents with abdominal pain?

Answer 43

if they are of childbearing age, you have to rule out ectopic pregnancy