8) Pelvic Osteology

Question 1

What is the bony pelvis made up from?

Answer 1

2 innominate (hip bones), sacrum and coccyx

Question 2

What is the linea terminalis?

Answer 2

Define true and false pelvis

Question 3

What is the sacral promontory?

Answer 3

Anterior superior edge of 1st sacral vertebrae

Question 4

What are the features of the gynecoid pelvis?

Answer 4

Round inlet
Non-prominent ischial spines 
Straight side wall 
Well curved sacrum 
Well rounded greater sciatic notch

Question 5

What is pelvic inlet defined by?

Answer 5

Wings of iliac bones, sacrum (pos) and pubic symphysis (ant)

Question 6

What is important to consider with reference to the pelvic outlet?

Answer 6

Distance between ischial tuberosities

Question 7

Which part of pelvis has obstetric relevance?

Answer 7

Lesser (true) pelvis

Question 8

What surrounds the lesser pelvis?

Answer 8

Ischial spines, lower sacrum and pubic symphysis

Question 9

What is clinically important to consider with reference to the pelvic inlet?

Answer 9

Antero-posterior diameter

Question 10

What is clinically important to consider with reference to the mid pelvis?

Answer 10

Straight side walls and distance between ischial spines

Question 11

Where is the obstetric conjugate measured between?

Answer 11

Sacral promontory to midpoint of pubic symphysis (minimum diameter)

Question 12

What conjugate is used in practice and where does it measure between?

Answer 12

Diagonal, inferior border of pubic symphysis to sacral promontory (measured through vagina)

Question 13

Give examples of difference between the male and females pelvis (4 differences):

Answer 13

Circular inlet (females) v heart shaped inlet (males)
Males have prominent ischial spines
Sub-pubic angle (between inferior rami of pubis) is narrow in males and wide females
Well rounded greater sciatic notch in females