Embryology

Question 1

name the congenital conditions characterised by more than 5 fingers and/or toes?

Answer 1

polydactyly

Question 2

what are the 2 types of syndactyly and what is the difference?

Answer 2

osseous - fusion of bones

cutaneous - webbing of fingers

Question 3

name the congenital conditions characterised by total absence of limbs.

Answer 3

amelia

Question 4

name the congenital conditions characterised by partial absence of limbs.

Answer 4

meromelia

Question 5

name the congenital conditions characterised by absence of some long bones.

Answer 5

phocomelia

Question 6

name the congenital conditions characterised by all bone present but are small.

Answer 6

micromelia

Question 7

a baby in born with an inverted foot, what is this condition?

Answer 7

congenital club foot

Question 8

a baby is born with a dislocated hip, what is the condition caused?

Answer 8

congenital dysplasia

Question 9

from what germ layer does the limbs develop from?

Answer 9

somatic lateral mesoderm

Question 10

what is responsible for the patterning of the limbs?

Answer 10

HOX genes

Question 11

absence of what HOX genes would cause absence of the radius and ulna?

Answer 11

HOXa-11 and HOXd-11

Question 12

when does the upper and lower buds appear?

Answer 12

upper 24 days

lower - 1 to 2 days after upper bud

Question 13

from what somites does the vertebrae develop from?

Answer 13

sclerotome

Question 14

what is the function of the HOX genes?

Answer 14

patterning of the limbs

they determine the skeletal elements in the parts of the limbs

Question 15

from what type of ossification does bones develop?

Answer 15

endochondral ossification for all bones except flat bones i.e. clavicle and neurocranium

Question 16

what other anomalies can occur with thalidomide?

Answer 16

meromelia partial absence of limbs
intestinal atresia
cardiac anomalies

Question 17

what are the cases of congenital club foot?

Answer 17

multifactors - genetic and environmental

abnormal position or restriction of movement of the foetus’s lower limb in utero

Question 18

what is the defect in congenital hip dislocation?

Answer 18

abnormal development of acetabulum and head of femur

Question 19

what is the pathological cause of syndactyly?

Answer 19

failure of notches to form in the digital plates

Question 20

is syndactyly more common in the hands or the feet?

Answer 20

feet > hands