Fetal Abnormalities Flashcards
What is acromelia?
Shortening of the bones of the hands or feet.
What is the aqueduct of Sylvius?
A channel between the third and fourth ventricles of the brain.
What does the banana sign indicate?
Crescent shape to the cerebellum displayed with a coexisting neural tube defect.
What is the corpus callosum? What function does it serve?
- A band of white matter tissue connecting the cerebral hemispheres
- Serves a function in both learning and memory.
Where is the Foramen of Monro located?
At the junction between the third ventricle and the paired lateral ventricles of the brain.
What is frontal bossing?
Protrusion or bulging of the forehead associated with hydrocephalus.
What is hydrocephalus?
Overt enlargement of the lateral ventricles secondary to an increase in intracranial pressure.
What does hypertelorism refer to?
Abnormally widespread position of the orbits.
What is hypotelorism?
Abnormally close position of the orbits.
What does the keyhole sign indicate?
Appearance of the dilated bladder superior to the obstructed male urethra.
What is concavity to the front bones of the fetal cranium associated with?
Spina bifida.
What does macroglossia refer to?
An excessively large tongue.
What is mesomelia?
Shortening of the middle portion of a limb.
What is rhizomelia?
Shortening of the proximal portion of a limb.
What does the steer sign indicate? What is it associated with?
- Enlargement and upper displacement of the third ventricle
- Associated with agenesis of the corpus callosum.
What is ventriculomegaly?
Ventricular enlargement characterized by excessive cerebrospinal fluid within the ventricles.
What is micromelia?
Shortening of all portions of a limb.
What is myelomeningocele?
A developmental defect of the central nervous system in which a hernial sac containing a portion of the spinal cord, its meninges, and cerebrospinal fluid protrudes through a congenital cleft in the vertebral column.
What does nuchal thickness measure?
The distance between the calvaria and posterior skin line.
What is proboscis?
Protrusion of nasal tissue above the orbits.
What is the vermis?
Structure located between the hemispheres of the cerebellum.
What are prominent sulcal markings associated with?
Abnormal migration of enchyma tissues.
What does it indicate if the skull is absent but the brain is present?
A significant developmental abnormality.
What are elevated alpha-fetoprotein levels associated with? 3
- Coexisting spinal defects
- Club foot
- Cleft lip, and palate.
What happens in the failure of callosal fibers to form?
Dilation and elevation of the third ventricle may be partial or complete.
What does outward angling and wide separation of the hemispheres indicate?
A potential cranial abnormality.
What is disproportionate enlargement of the occipital horns called?
Colpocephaly
Arachnoid cyst are cysts that arise from? 3
A cyst that can result from
1. Trauma
2. Infarction
3. Infection.
What is Dandy-Walker malformation?
A congenital malformation of the cerebellum with associated maldevelopment of the fourth ventricle.
What is the banana sign in sonography?
Compressed shape of the cerebellum through foramen magnum.
What is the lemon-shaped cranium associated with?
Arnold-Chiari malformation.
What does Dandy-Walker syndrome involve?
Enlarged posterior fossa and prominent posterior fossa.
What are common causes of Dandy-Walker syndrome? 3
- Alcohol abuse
- Autosomal recessive disorder
- Viral infection.
What is the significance of a cisterna magna greater than 10 mm?
It indicates potential abnormalities.
What is ventriculomegaly?
Increase in ventricular volume generally caused by outflow obstruction or decreased cerebrospinal fluid production.
What is hydranencephaly?
A condition where brain tissue is replaced by cerebrospinal fluid.
What characterizes alobar holoprosencephaly?
Large central single ventricle and fused thalami.
What is cyclopia?
A severe form of holoprosencephaly.
What is the mildest form of holoprosencephaly?
Lobar holoprosencephaly with two large lateral ventricles.
What is associated with spina bifida? (in the head)
Bilateral indentation of the occipital bone may be a normal finding.
What is anencephaly?
A result of infarction or hemorrhage leading to a small biparietal diameter.
What does decreased head circumference indicate? What is considered below normal?
It can indicate conditions like encephalocele, measuring more than 3 SD below normal.
What is characterized by a sloping forehead?
Anechoic mass within an area of the brain.
What is spina bifida?
A neural tube defect characterized by the failure of the cephalic end of the neural tube to close completely.
Associated with bulging eyes (froglike face) and absence of the cranial vault.
What disorder is midline brain shift associated with?
It is associated with Trisomy 18.
What are the sonographic findings of agenesis of the corpus callosum?
Prominent or dilated third ventricles and a single fluid space close to midline.
Variable in shape.
What is a cerebral arteriovenous malformation (AVM)?
A condition characterized by a dilated vein of Galen and turbulent blood flow within associated ventriculomegaly.
What is the significance of elevated alpha-fetoprotein (AFP) levels?
Elevated AFP levels can indicate neural tube defects and other malformations.
Associated with amniotic band syndrome and polyhydramnios.
Caudal regression is a condition more common with patients with what disorder?
A condition associated with skeletal dysplasia and more common in patients with diabetes.
What characterizes an encephalocele?
A defect in the bony calvarium allowing herniation of intracranial contents.
More common in the occipital region.
What is a cystic hygroma?
A spherical fluid-filled or complex mass extending from the calvaria.
What is the appearance of a cloverleaf skull deformity?
Characterized by a bony calvarial defect and herniation of brain tissue.
What does the term ‘occulta’ refer to? What happens to the AFP in this level?
A type of spina bifida where the defect is covered by normal soft tissues and has a normal AFP level.
What does ‘aperta’ indicate in spina bifida? What happens to the AFP in this level?
A type of spina bifida where the defect is uncovered, associated with elevated AFP levels.
What is anophthalmia?
The absence of the globe or the orbit, often associated with failure of the optic vesicle to form.
Documented best on the transaxial view at the level of the orbits.