Cranial Growth and Ageing

Question 1

How may the centres of ossification in the occipital bone appear?

Answer 1

Fused or separated

Question 2

When do the centres of ossification fuse by?

Answer 2

School age

Question 3

What is the sphenoid-occipital synchondrosis?

Answer 3

The cartilaginous union between the sphenoid and occipital bone at the base of the skull

Question 4

When does the sphenoid-occipital synchrondosis close?

Answer 4

Age 16-25

Question 5

What is the anterior fontanelle?

Answer 5

Soft diamond shaped part at the front of the skull which allows for cranial growth

Question 6

When does the anterior fontanelle close?

Answer 6

98% closed by the age of 2

Question 7

What is the metopic suture?

Answer 7

Connective tissue structure which separates the two halves of the frontal bone of the skull

Question 8

When does the metopic suture close?

Answer 8

Fuses at around the age of 9 months then disappears at around 6 years old

Question 9

What is the mastoid process?

Answer 9

Conical prominence projecting from the undersurface of the mastoid portion of the temporal bone

Question 10

Where is the mastoid process located?

Answer 10

Behind the external acoustic meatus

Question 11

When can the mastoid process be found?

Answer 11

Distinct at around 2 years old

Question 12

Describe the tympanic ring

Answer 12

Starts as a tympanic ring but lengthens to a plate

Question 13

What is the mental symphysis?

Answer 13

Infused centre of the mandible

Question 14

When does the mental symphysis fuse?

Answer 14

Fused by 7-8 months

Question 15

What is the angle of the mandible?

Answer 15

Angle between body and ramus which is obtuse

Starts as markedly obtuse and gets less so until teeth are loss

Question 16

What is a synchondrosis?

Answer 16

An almost immovable joint between bones bound by a layer of cartilage

Question 17

Where is the sphenoid-occipital synchondrosis?

Answer 17

Between the basisphenoid and basiocciput bones which together form the clivus

Question 18

What is an ossification centre?

Answer 18

A point at which formation of cartilage begins

Question 19

How many ossification centres does the occipital bone develop from?

Answer 19

6

Question 20

What is a fontanelle?

Answer 20

The space between the bones of an infant’s skull where the sutures intersect

Question 21

Why are fontanelles important stuctures in the developing skull?

Answer 21

They are covered by tough membranes that protect the underlying soft tissues and skull

Question 22

How many fontanelles are there?

Answer 22

4

Question 23

When does the anterior fontanelle close?

Answer 23

Between 9 and 19 months

Question 24

When does the posterior fontanelle close?

Answer 24

By 1 or 2 months, may be closed at birth

Question 25

When does the mastoid fontanelle close?

Answer 25

Between 6 and 18 months

Question 26

When does the sphenoid fontanelle close?

Answer 26

Around 6 months after birth

Question 27

Label the cranial bones

Answer 27

Question 28

Label the facial bones

Answer 28

Question 29

Label the fontanelles

Answer 29

Question 30

Label the fetal sutures

Answer 30