Congenital Pathology

Question 1

What structure gives rise to the fourth ventricle?

Answer 1

The rhombencephalon

Question 2

What structure gives rise to the third ventricle?

Answer 2

The diencephalon

Question 3

What structure gives rise to the three germinal layers?

Answer 3

The primitive streak

Question 4

Neurenteric canals arise from ____________.

Answer 4

persistent canal between amniotic sac and yolk sac

Question 5

Secondary neurulation occurs in a structure called the ___________.

Answer 5

caudal cell mass

Question 6

The completed neural tube sends out nerves that split the ______________ and connect to myotomes.

Answer 6

somites

Question 7

Failure of the neural tube to close is called _____________.

Answer 7

neuroschisis

Question 8

Describe holoprosencephaly.

Answer 8

A disorder in which the telencephalon fails to develop into two hemispheres

Question 9

Cranioraschisis totalis results from ____________.

Answer 9

absolute failure of the neural tube to close

Question 10

Eyes are outpouchings of _____________.

Answer 10

the diencephalon

Question 11

The prosencephalon gives rise to the __________.

Answer 11

telencephalon and diencephalon

Question 12

Encephaloceles can contain _____________.

Answer 12

subarachnoid layer (in which the contents would be CSF) or subdural (in which the contents would be brain tissue)

Question 13

Myelomeningoceles are ____________.

Answer 13

failures of the posterior neural tube to close

Question 14

Prognosis of myelomeningoceles depends on ____________.

Answer 14

level of the failure; higher levels decrease the likelihood of future ambulation

Question 15

Fatty filum terminale leads to _____________.

Answer 15

tethering of the spinal cord, which prevents its normal ascension in relation to the vertebral column

Question 16

Bladder problems are common in those with ___________.

Answer 16

tethering of the spinal cord

Question 17

Which Chiari malformation is the most mild?

Answer 17

Chiari I

Question 18

What characterizes Chiari II (aka Arnold-Chiari)?

Answer 18

Meningomyelocele (failure of the neural tube) leading to bulging of the cerebellar vermis into the foramen magnum (thought to arise from the failure of the fluid support of the neural tube) and subsequent hydrocephalus (from the occlusion of the cerebral aqueduct)

Question 19

The ____________ protrude into the foramen magnum in Chiari I malformation.

Answer 19

cerebellar tonsils

Question 20

Some of the pain tracts that pass the midline come from ______________.

Answer 20

above and below that spinal level

Question 21

Symptomatic Chiari I can be treated with _____________.

Answer 21

surgical decompression

Question 22

When do most neural tube defects occur?

Answer 22

During neural tube closure, during the fourth week of development

Question 23

Importantly, those with holoprosencephaly have normal ______________.

Answer 23

midbrain and hindbrain

Question 24

Describe Dandy-Walker malformation.

Answer 24

A large cyst develops where the cerebellum lies, thereby preventing its growth

Question 25

What Alzheimer’s protein is found on chromosome 21?

Answer 25

Amyloid precursor protein –(“two Ps and 1 A”)

Question 26

Which kind of Chiari is not a neural tube defect?

Answer 26

Type I – it is “a size 5 brain in a size 4 skull”

Question 27

Purely genetic CNS malformations are ___________.

Answer 27

rare (only 8%)

Question 28

The primitive cerebral hemispheres develop by which week of gestation?

Answer 28

7

Question 29

What are the average weights of the newborn brain and adult brain?

Answer 29

400 grams and 1,200 grams

Question 30

Spina bifida occulta is most often a _____________ finding.

Answer 30

incidental, benign

Question 31

What are meningoceles?

Answer 31

Skin-covered, CSF-filled masses continuous with the CSF of the spinal cord; synonymous with encephalocele

Question 32

__________ are like less severe forms of myelomeningoceles.

Answer 32

Dorsal sinus tracts

Question 33

What is spina bifida occulta?

Answer 33

Failure of the vertebral arch to fully close

Question 34

Describe syringomyelia.

Answer 34

A condition in which a fluid-filled sac develops in the spinal cord due to obstruction of normal flow within the central canal

Question 35

Agenesis of the cerebellar vermis and cystic occlusion of the fourth ventricle are characteristic of ___________.

Answer 35

Dandy-Walker malformations

Question 36

Describe the differences between porencephaly, schizencephaly, and hydranencephaly.

Answer 36

All relate to cerebrovascular events that lead to clean destruction of brain tissue: porencephaly is a large, unilateral hole; schizencephaly is bilateral holes; and hydranencephaly is near complete destruction of one hemisphere.

Question 37

What causes cranioraschisis totalis?

Answer 37

Complete failure of the neural tube to close

Question 38

What cells give rise to sacrococcygeal teratomas?

Answer 38

The pluripotent cells of the primitive streak

Question 39

Rather than arising from a defect in the neural tube, Chiari I malformations are thought to stem from _______________.

Answer 39

mesodermal defects (the mesoderm that produces the skull base)

Question 40

What is the peak developmental period for prosencephalon development?

Answer 40

2-3 months

Question 41

Ulegyria results from ______________.

Answer 41

perinatal watershed strokes