17.1 Developmental Anomalies

Question 1

What is the general cause of neural tube defects?

Answer 1

Failure to close the neural tube - associated with low folate levels prior to conception

Question 2

What do the neural crests go on to become?

Answer 2

PNS

Question 3

What does the wall of the neural tube become?

Answer 3

CNS

Question 4

What does the lumen of the neural tube become?

Answer 4

Ventricles and Spinal Canal

Question 5

Anencephaly

Answer 5

Absence of skull and brain with a frog-like appearance of the fetus

Question 6

Spina Bifida Occulta

Answer 6

Failure of the posterior vertebral arch to close that leads to a dimple or a patch of hair overlying the vertebral defect

Question 7

Cerebral Aqueduct Stenosis

Answer 7

Congenital stenosis of the channel that drains CSF from the 3rd to 4th ventricles - CSF accumulation in the ventricles

Question 8

Dandy-Walker Malformation

Answer 8

Failure to develop the cerebellar vermis that presents with a massively dilated 4th ventricle and absent cerebellum

Question 9

Arnold-Chiari Malformation

Answer 9

Extension of the cerebellar tonsils through the foramen magnum that can lead to the obstruction of CSF flow