Embryology

Question 1

When do the early stages of limb development begin?

Answer 1

Near the end of the 4th week

Question 2

On what day does the upper limb bud appear?

Answer 2

Day 24

Question 3

On what day does the lower limb bud appear?

Answer 3

Day 25-26

Question 4

Which genes determine which skeletal element is formed?

Answer 4

HOX genes

Question 5

What would happen if you removed HOXa 11 and HOXd 11?

Answer 5

The radius and ulna would not form

Question 6

Which cellular process is responsible for the tissue breakdown in the interdigital regions?

Answer 6

Programmed cell death (apoptosis)

Question 7

What is the term for the total absence of a limb?

Answer 7

Amelia

Question 8

What is the term for the partial absence of a limb?

Answer 8

Meromelia

Question 9

What is the term for long bone absence?

Answer 9

Phocomelia

Question 10

What is the term for when all parts of a limb are present but small?

Answer 10

Micromelia

Question 11

What is the term for the presence of more than 5 digits on the hands or feet?

Answer 11

Polydactyly

Question 12

What does syndactyly mean?

Answer 12

Webbing between the digits, either cutaneous or osseous

Question 13

Which birth defect of the limbs was caused by maternal ingestion of thalidomide?

Answer 13

Meromelia

Question 14

What is the most common type of congenital club foot?

Answer 14

Talipes varus

Question 15

How common is club foot?

Answer 15

1 baby in every 1000 born in the UK

Question 16

How do you describe the feet of infants born with club foot?

Answer 16

Sole of the foot is turned medially and the foot is inverted