Foetal Skull

Question 1

Name the bones of the foetal skull

Answer 1

• 2 frontal bones
• 2 parietal bones
• 2 temporal bones
• 1 occipital bone

Question 2

What parts makes up the foetal skull?

Answer 2

• Vault (main bones)
• Base
• Face

Question 3

What is the name of the brow region?

Answer 3

Sinciput

Question 4

What are sutures?

Answer 4

Soft areas of fibrous tissue where ossification is not complete

Question 5

Name the sutures of the foetal skull

Answer 5

1. Frontal (between frontal bones)
2. Coronal (between the frontal and parietal bones)
3. Sagittal (between parietal bones)
4. Lamboidal (between the occipital and parietal bones)

Question 6

What is a fontanelle?

Answer 6

A membranous non-ossified area where sutures meet

Question 7

What are the names of the fontanelles?

Answer 7

Anterior fontanelle (bregma)
Posterior fontanelle (lambda)

Question 8

Describe the bregma

Answer 8

• Diamond shaped (4 attachment points)
• Closes at 18 months
• Larger than the lambda

Question 9

If the bregma is felt on VE, what position is the baby likely to be in?

Answer 9

Direct OP with deflexed head

Question 10

Describe the lambda

Answer 10

• Triangular (3 attachment points)
• Closes at 6 weeks
• Smaller than the bregma

Question 11

If the lambda is felt on VE, what position is the baby likely to be in?

Answer 11

OA with a flexed head

Question 12

What are the diameters of the skull?

Answer 12

• Suboccipitobregmatic
• Suboccipitofrontal
• Occipitofrontal
• Mentovertical
• Submentovertical
• Submentobregmatic
• Biparietal
• Bisacromial
• Bitrochanteric

Question 13

Describe the suboccipitobregmatic diameter

Answer 13

• Below the occipital bone to the centre of the bregma

- 9.5cm

Question 14

Describe the suboccipitofrontal diameter

Answer 14

• Below the occipital bone to the centre of the frontal suture
• 10cm

Question 15

Describe the occipitofrontal diameter

Answer 15

• Occipital protuberance to the centre of the frontal suture

- 11.5cm

Question 16

Describe the mentovertical diameter

Answer 16

• From the chin straight upwards to the highest point on the vertex
• 13.5cm

Question 17

Describe the submentovertical diameter

Answer 17

• From the point where the chin meets the neck straight upwards to the highest point of the vertex
• 11.5cm

Question 18

Describe the submentobregmatic diameter

Answer 18

• From the point where the chin meets the neck to the centre of the bregma
• 9.5cm

Question 19

Describe the biparietal diameter

Answer 19

• Stretches between the parietal eminences

- 9.5cm

Question 20

Describe the bisacromial diameter

Answer 20

• Stretches between the 2 shoulder blades

- 12cm

Question 21

Describe the bitrochanteric diameter

Answer 21

• Stretches between the greater trochanters of the femurs

- 10cm

Question 22

Describe a vertex presentation

Answer 22

• When head is well flexed, suboccipitobregmatic and biparietal diameters present
• When head is deflexed, occipitofrontal and biparietal diameters present

Question 23

Describe a face presentation

Answer 23

Head is extended and the submentobregmatic and bitemporal diameters present

Question 24

Describe a brow presentation

Answer 24

Head is partially extended and the mentovertical and bitemporal diameters present