Chapter 59 Flashcards
Anencephaly is also know as …
aprosencephaly or atelacephaly
The most common neural tube defect
anencephaly
Anencephaly which means absence of the _____, is caused by failure of closure of the neural tube at the cranial end,
brain
In anencephaly the reminate brain is covered by a thick membrane called _________ or _________.
angiomatous stroma, cerebrovasculosa
Anencephaly is a lethal disorder, with up to ____ of cases resulting in fetal demise.
50%
Acrania, also known as _________, is a lethal anomaly that manifests as absence of the cranial bones with the presence of complete, although abnormal, development of the cranial hemispheres.
exencephaly
A neural tube defect in which the meninges alone or the meninges and the brain herniate through a defect in the calvarium.
cephalocele
A term used to describe herniation of the meninges AND brain through the defect.
enecphalocle
Describes the herniation of only the meninges
cranial meningocele
Cepholoecles occur at a rate of 1-3 in _______ live births.
10,000
In ____ of cases cephaloceles are located at the midline and involve the occipital bone.
75%
Chromosomal anomalies and syndromes have been identified with cephoceles, including trisomy ___ and ________.
13, Meckel-Gruber syndrome
Meckel-Gruber syndrome is an autosomal-recessive disorder characterized by encephalocele, _________ , and _________.
polydactyly, polycystic kidneys
Cephaloceles located off midline are usually the result of __________.
ammniotic band syndrome
Cephaloceles maybe confused with _________ although they lack a cranial defect.
cystic hygroma
Encompasses a wide range of vertebral defects that result from failure of neural tube closure.
spina bifida
Spina Bifida occurs most commonly along the _______ and ______ regions.
lumbar, sacral
Results from the abnormal cleavage of the prosencephalon (forebrain)
holoprosencephaly
Holoprosencephaly is often associated with ______ abnormalities.
facial
Facial anomalies identified with holoprosencephaly…
cyclopia, hypertelorism, an absent nose, a flattened nose with single nostril, and proboscios (think trisomy 13)
Consists of the combination of hyoptelorism with a normally placed nose with a single nostril.
cebocephaly
Severe hypotelorism with a proboscis superior to the eyes.
ethmocephaly
Chromosomal anomalies must also be considered if holoprosencephaly is present, especially _________.
trisomy 13
The _________ is a fiberous tract that connects the cerebral hemispheres and aids in learning and memory.
corpus callosum
Cause of agenisis of the corpus callosum is thought to involve a vascular disruption or inflammatory lesion before _______.
12 weeks
Aqueduct stenosis results from obstruction, atresia, or stenosis of the aquduct of sylvius causing _______.
ventriculomegaly
The aquaduct of sylvius connects the _____ and _____ ventricles. Which causes the enlargement of the lateral ventricles.
third and forth
Aquaductal stenosis is usually sporadic, but may result from __________, such as cytomegalovirus, rubuella, and toxoplasmosis.
intrauterine infection
Primary aquaductal stenosis is usually _______ and an autosomial-recessive inheritance.
X-linked
Aneurysm of the vein of Galen, also known as…
A vein of Galen malformation
Choroid plexus cysts often resolve by ______ weeks gestation.
22 to 26
Rare disorder charcterized by clefts in the cerebral cortex.
schizencephaly
Schizencephaly has been associated with…
congenital infection, drugs and other toxic exposures, vascular accidents, and metabolic abnormalities.
Destruction of the cerebral hemispheres by occlusion of the internal carotid arteries.
hydranencephaly
Because microcephaly may manifest late in pregnancy, diagnosis before _______ weeks gestation may be impossible.
24
