Laboratory 18: The Fetal Skeleton

Question 1

How many bones in the adult skeleton?

Answer 1

206

Question 2

How many bones in the fetal skeleton?

Answer 2

275.

Question 3

Why are there more bones in the fetal skeleton?

Answer 3

Due to the numerous ossification centers and epiphyseal plates present for many of the bones of the appendicular skeleton

Question 4

How does development of the fetus occur?

Answer 4

Progresses from cephalic to caudual regions of the body

Question 5

What is a result from the way the fetus grows?

Answer 5

There is a noticeable difference between the proportions of the head, the entire body and the upper and lower limbs between a fetus and adult

Question 6

What are the bones of early ossification?

Answer 6

The bones most important for protection are among the early ossification sites

Question 7

When does the ossification process occur?

Answer 7

Occurs during fetal development and continues through childhood growth.

Question 8

What is intramembranous ossification?

Answer 8

Intramembranous ossification originating mesenchyme forms the flat bones of the cranium, some facial bones and portions of the mandible and clavicle.

Question 9

What is endochondral ossification?

Answer 9

Originating from hyaline cartilage forms most of the skeleton

Question 10

What are fontanels?

Answer 10

Areas of incomplete ossification of the flat bones of the skull of an infant are called fontanels.

Question 11

What do fontanels allow for?

Answer 11

Fontanels allow for compression of the cranium during vaginal delivery and for some additional brain development after birth.

Question 12

What fontanels close within the first year of life?

Answer 12

Posterior and lateral

Question 13

When does the anterior fontanel close?

Answer 13

The anterior fontanel does not close until nearly two years of age.

Question 14

What are the types of fontanels?

Answer 14

Mastoid fontanel, sphenoid fontanel, posterior fontanel, anterior fontanel

Question 15

What are the differences between the facial portion of an adult skull vs fetal?

Answer 15

The facial portion of a fetal skull at birth represents about one eighth of the entire skull where as the adult facial portion of the skull represents nearly one half of the complete skull.

Question 16

Why does the fetal skull have a small face?

Answer 16

The small face is related to the undersized maxillae, maxillary sinuses, mandible and lack of teeth eruptions and nasal cavities.

Question 17

What happens to the size of the cranium as fetal growth progresses?

Answer 17

As the growth of the fetus advances the relative size of the cranium becomes smaller as the size of the face increases

Question 18

When does most of the development of an upper limb occur?

Answer 18

Much of the development of an upper limb occurs during fetal development especially during the second trimester.

Question 19

When does most of the development of a lower limb occur?

Answer 19

The rapid development of the lower limb is much greater after birth