repro 4.2 osetology of the pelvis

Question 1

What 4 bones make up the pelvis?

Answer 1

2 inonimate bones
sacrum
coccyx

Question 2

What are the features of the innonimate bones? (hip bones)

Answer 2

iliac crest
the ischial spine
ischial tuberosits

Question 3

What is the linea terminalis?

Answer 3

The point at which you enter the true pelvis from the false pelvis.

Made of:

• pubic crest
• pectineal line
• arcuate line

Question 4

What problems may be caused by the sacrum?

Answer 4

The sacral pomontory may cause problems with the birthing of the foetus.

Question 5

What are the borders of the pelvic inlet?

Answer 5

-linea terminalis (pubic crest, pectinate line, arcuate line)
-sacral ala
Sacral promontory

Question 6

What is the name given to a pelvis which is ideal for birth?

Answer 6

Gynecoid

Question 7

What are features of a gynecoid pelvis?

Answer 7

• round pelvic inlet
• straight pelvic walls (not tapered)
• not too prominent ischial spines
• well rounded greater sciatic notch
• well curved sacrum
• sub pubic arch >90 degrees

Question 8

What is the true pelvis?

Answer 8

The solid bony canal of the pelvis which is of obstetric relevance.

Question 9

What is the false pelvis?

Answer 9

The part of the pelvis above the pelvic inlet.

Has no obstetric relevance as it is more than big enough for the foetus.

Question 10

What are the 4 pelvic planes?

Answer 10

• pelvic inlet
• plane of greatest diameter
• plane of least diameter
• pelvic outlet

Question 11

What is the pelvic inlet?

Answer 11

• linea terminalis
• sacrum
• coccyx
• pubic symphesis

Question 12

What is the plane of greatest diameter?

Answer 12

• the AP diameter from the posterior pubic symphesis to the junction between S2/3.
• Laterally is between the acetabulum through the ischial spines.

Question 13

What is the plane of least diameter?

Answer 13

-AP from the posterior pubic symphesis to the junction between S4/5.

Question 14

What is the pelvic outlet?

Answer 14

• pubic symphesis
• ichiopubic rami
• ischial tuberosities
• sacrotuberous ligaments
• tip of the coccyx.

Question 15

What do midwives assess to see if the female is likely to have difficulty giving birth?

Answer 15

• AP diameter. (via palpation)
• straight walls of the pelvis
• bi-spinous diameter (too small, foetus may get stuck)
• infrapubic angle
• distance between ischial tuberosities.

Question 16

What are the conjugates of the pelvis?

Answer 16

• obstetric conjugate
• diagonal conjugate (measured)

They measure the minimum AP diameter of the pelvis

Question 17

How do you measure/what is the obstestric conjugate?

Answer 17

from the sacral promontory to the mid point of the pubic symphesis.

Question 18

How do you meausre/what is the diagonal conjugate?

Answer 18

from the sacral promontory to the inferior border of the pubic symphesis.

Question 19

What are the ligaments of the pelvis?

Answer 19

sacrospinous ligament (sacrum to ischial spine)

sacrotuberous ligaments (sacrum to ischial tuberosity)

Question 20

What’s the function of the pelvic ligaments during birth?

Answer 20

They allow a little bit of movement of the pelvis during childbirth. Allow a bit of ‘give’

Question 21

During pregnancy, what hormone is released to allow easier birthing?

Answer 21

Progesterone, allows for slight softening of the pelvic joints and ligaments, to allow them to move more during birth.

Question 22

What different features are there in an android pelvis compared to a gynecoid pelvis?

Answer 22

• tapering walls
• smaller angle of sub-pubic arch
• heavier pelvis
• heart shaped outlet (instead of round)
• narrower true pelvis
• more prominent ischial spines (–> less well rounded greater sciatic notch)

Question 23

The pubic inlet is the point of division between what 2 parts of the pelvis?

Answer 23

• false pelvis

- true pelvis

Question 24

Why can you not directly measure the obstetric conjugate during examination?

Answer 24

The bladder is in the way

Question 25

What does the sacrotuberous ligament lead to the formation of?

Answer 25

The sciatic foreamen

Question 26

What does the sacrospinous ligament lead to the formation of?

Answer 26

The division of the sciatic foramen into the greater and lesser sciatic foramen.