Fetal skull

Question 1

Define the calvaria

Answer 1

The skull cap

Question 2

Define fontanelle

Answer 2

The soft membranous gap (aka sutures) between the cranial bones that make up the calvaria

Question 3

State 4 skull sutures

Answer 3

1. Frontal suture (frontal bone)
2. Coronal suture (parietal bone)
3. Sagittal suture (parietal bone)
4. Lamboid suture (occipital bone)

Question 4

State the 6 fontanelles in the calvaria

Answer 4

1. Anterior (bregma) fontanelle
2. Posterior fontanelle
3. Sphenoid fontanelle
4. Mastoid fontanelle

Question 5

Give the boundary of the anterior fontanelle and when it fuses

Answer 5

Bounded by coronal suture and frontal suture and sagittal suture (fuses ~ 18 months)

Question 6

Give the boundary of the posterior fontanelle and when it fuses

Answer 6

Bordered by sagittal suture and lambdoid suture (fuses~3 months)

Question 7

Give the boundary of the sphenoidal fontanelle and when it fuses

Answer 7

On the lateral side of skull above sphenoid bone (fuses ~ 6 months)

Question 8

When does the mastoid fontanelle fuse

Answer 8

Between 6-18 months

Question 9

State 2 functions of fontanelles in children

Answer 9

1. Enables skull to be more flexible during childbirth

2. Allows for rapid stretching as the brain grows rapidly

Question 10

What is the condition called when fontanelles fuse?

Answer 10

Cleidocranial dysplasia

Question 11

Define the terms ‘moulding’ and ‘Caput’

Answer 11

Moulding = Bones overlap each other 
Caput = swelling of fetal head

Question 12

State the 6 longitudinal diameters of the fetal skull

Answer 12

1. Suboccipitobregmatic (9.5cm)
2. Suboccipitofrontal (10cm)
3. Occipitofrontal (11.5cm)
4. Submentobregmatic (9.5cm)
5. Mentovertical (13.5cm)
6. Submentovertical (11.5cm)