1: Anatomy - Bony pelvis, pelvic fracture and labour

Question 1

What is another name for the hip bone?

Answer 1

Innominate bone

Question 2

What are the three parts of each innominate bone?

Answer 2

Ilium

Ischium

Pubic bone

Question 3

At which joints do the innominate bones

a) connect anteriorly
b) connect to the sacrum posteriorly?

Answer 3

a) Pubic symphysis
b) Sacroiliac joints

Question 4

At which level does the dura end?

Answer 4

S2

Spinal cord ends at L2 (conus medullaris) but dura continues with the cauda equina

Question 5

What spinal level is the transtubercular plane found at?

Answer 5

L5

Question 6

Why is the ischial spine an important feature?

Answer 6

Sacrospinous ligament attaches to it

And the pudendal nerve traverses around the sacrospinous ligament

Question 7

Which nerve twists around the sacrospinous ligament?

Answer 7

Pudendal nerve (S2-4)

Question 8

Which muscle group attaches to the ischial tuberosity posteriorly?

Answer 8

Hamstrings group

Medial to lateral: semimembranosus, semitendinosus, biceps femoris

Question 9

What happens to the sacrospinous and sacrotuberous ligaments during pregnancy?

Answer 9

Relaxation

Question 10

Which bony feature of the ischium forms the inferior border of the obturator foramen?

Answer 10

Ischiopubic ramus

Question 11

How does the pubic arch differ in appearance in males versus females?

Answer 11

Males - smaller angle (**/** shape)

Females - greater angle, wider pelvic inlet/outlet for childbirth

Question 12

Where does the pelvis tend to fracture?

Answer 12

Multiple places

bony ring

Question 13

Pelvic fractures often occur alongside joint ___.

Answer 13

dislocations

Question 14

Which neurovascular structures may be disrupted by pelvic trauma?

Answer 14

Common iliac artery

Common iliac vein

Sacral plexus

Question 15

Why is pelvic haemorrhage so dangerous?

Answer 15

Internal bleeding

Occurs without visible signs until life-threatening

Question 16

What are the structural differences between the male and female pelvis?

Answer 16

In females:

deeper pubic arch

greater AP and transverse diameters of pelvic inlet and outlet

shallower pelvic cavity

compared to men

Question 17

How many frontal bones does the foetal skull have?

Answer 17

Two

Question 18

Which structures allow the bones of the foetal skull to move and slide over one another during childbirth?

Answer 18

Anterior and posterior fontanelles

Question 19

When may the anterior and posterior fontanelles be

a) bulging
b) depressed?

Answer 19

a) Increased intracranial pressure (e.g hydrocephalus)

b) Malnutrition / dehydration

Question 20

What are the three sutures found in the foetal skull?

Answer 20

Sagittal suture

Coronal suture

Lambdoid suture

Question 21

What area is found within the borders made by the anterior and posterior fontanelles and the parietal prominences?

Answer 21

Vertex

Question 22

In the context of childbirth, what is moulding?

Answer 22

Sliding of skull bones over one another

Reduces diameter of foetal head during childbirth

Question 23

Which bony features form the pelvic inlet?

Answer 23

Sacral promontory

Ilium

Superior pubic ramus

Pubic symphysis

Question 24

Which bony features form the pelvic outlet?

Answer 24

Pubic symphysis

Ischiopubic ramus

Ischial tuberosities

Sacrotuberous ligaments

Coccyx

Question 25

The foetal head has frontotemporal (front to back) and biparietal (side to side) diameters.

Which diameter is greater?

Answer 25

Frontotemporal diameter > Biparietal diameter

i.e a newborn’s head should be longer than it is wide

Question 26

What ligaments form the

a) greater
b) lesser sciatic foramen?

Answer 26

a) GREATER SCIATIC FORAMEN - both

b) LESSER SCIATIC FORAMEN - both