CH 59 & 60 OB 2

What three things are evaluated as a part of the nasal triad?

-nostril symmetry -nasal septum integrity -continuity of the upper lip; rule out cleft

What is the occurrence of congenital anomalies of the face?

1 in every 600 births

What is the optimal age for measuring the nuchal translucency? What is considered an abnormal measurement?

11-13w6d >3 mm

What is the normal range of measurement for the lateral ventricles?

< 10 mm average is 6.5 mm

What is considered an abnormal measurement of the nuchal fold?

>5 mm

"Absent Skull-Present Brain" •Is lethal anomaly; also known as exencephaly

Acrania

Usually progresses to anencephaly as brain slowly degenerates as result of exposure to AF

Acrania

An absent cavum septum pellucidum is a distinguishing characteristic in which fetal head anomaly?

Agenesis of corpus callosum

•Singular monoventricle brain tissue that is small •Absence of interhemispheric fissure •Absence of cavum septum pellucidum

Alobar Holoprosencephaly

"Absence of the brain" •Most common neural tube defect • "Frog face"

Anencephaly

Is caused by failure of closure of neural tube at cranial end

Anencephaly

Result is absence of cranial vault, complete or partial absence of forebrain, presence of brainstem, midbrain, skull base, facial structures

Anencephaly

presents invariably with hydrocephalus caused by the cerebellar vermis

Arnold Chiari type II

Fetuses with myelomeningoceles often present with cranial defects associated with _______

Arnold-Chiari (type II) malformation

_____ consists of combination of hypotelorism with normally placed nose with single nostril.

Cebocephaly

Neural tube defect in which meninges alone or meninges and brain herniate through defect in calvarium (involves occipital bone)

Cephalocele

Manifests with agenesis or hypoplasia of cerebellar vermis with resulting dilation on fourth ventricle and enlargement of posterior fossa.

Dandy Walker Malformation

defect that may have varying degrees of severity; it manifests with agenesis or hypoplasia of the cerebellar vermis with resulting dilation on the fourth ventricle and enlargement of the posterior fossa

Dandy Walker Malformation

•Posterior fossa cyst •Splaying of cerebellar hemispheres as result of complete or partial agenesis of cerebellar vermis •Enlarged cisterna magna caused by cerebellar vermis anomaly and posterior fossa cyst •Ventriculomegaly

Dandy-Walker Malformation

_______ consists of severe hypotelorism with proboscis superior to eyes.

Ethmocephaly

This may be observed in a fetus with a lemon-shaped skull ( from spina bifida)

Frontal bossing

median cleft face syndrome consisting of a range of midline facial defects involving the eyes, forehead, and nose.

Frontonasal dysplasia

What syndrome is associated with ear malformations?

Goldenhar's syndrome

The facial anomalies include cyclopia, hypotelorism, an absent nose, a flattened nose with a single nostril, and a proboscis.

Holoprosencephaly

•Destruction of cerebral hemispheres by occlusion of internal carotid arteries •Brain parenchyma destroyed and replaced by cerebrospinal fluid

Hydranencephaly

_______ is defined as an enlarged cistern magna.

Megacisterna magna (MCM)

"Meaning-Split" The brain appears "split" into anterior and posterior parts.

Schizencephaly

•Wide range of vertebral defects that result from failure of neural tube closure •Meninges and neural elements may protrude through defect.

Spina Bifida

Premature closure of the metopic suture (causes forehead to have an elongated appearance in a sagittal plane, and appear triangular shaped in the axial plane)

Trigonocephaly

•Rare arteriovenous malformation •Vein will be enlarged and communicate with normal-appearing arteries.

Vein of Galen Aneurysm

What conditions are commonly associated with fetal hydrocephalus?

acqueductal stenosis arachnoid cysts vein of galen aneurysms

condition associated with anencephaly in which there is complete or partial absence of the cranial bones

acrania

What anomalies are most commonly associated with anencephaly?

acrania cephalocele amniotic band syndrome

a vascular disruption or inflammatory lesion before 12 weeks gestational age

agenesis of the corpus callosum

What is the most severe form of holoprosencephaly and what are some of the related findings?

alobar singular monoventricle brain tissue that is small and may have a cup, ball, or pancake configuration

What is the most common open neural tube defect?

anencephaly

neural tube defect characterized by the lack of development of the cerebral and cerebellar hemispheres and cranial vault; this abnormality is incompatible with life

anencephaly

results rom obstruction, atresia, or stenosis of the aqueduct of sylvius causing ventriculomegaly

aqueductal stenosis

Differential considerations for dandy walker malformation should include _____

arachnoid cyst

What is a differential consideration for Dandy-Walker malformation?

arachnoid cysts cerebellar hypoplasia

The best plane to sonographically evaluate the spine for spina bifida is ________ plane.

axial/transverse

Spina bifida Changes shape of cerebellum, giving it "_____" appearance

banana

protrusion of the brain from the cranial cavity

cephalocele

What is the most common congenital anomaly of the face?

cleft lip (with or without cleft palate)

Obstruction may be outside of ventricular system, such as with arachnoid cyst; is referred to as _____ hydrocephalus

communicating

________ is fibrous tract that connects the cerebral hemispheres.

corpus callosum

early ossification of the calvarium with destruction of the sutures; hypertelorism frequently found in association; sonographically the fetal cranium may appear brachycephalic

craniosynostosis

fluid-filled structure, often with separations, initially surrounds the neck but may extend upward to the head or laterally to the body; dilation of jugular lymph sacs because of improper drainage of the lymphatic system into the venous system

cystic hygroma

What is the most common neck mass? What percentage of these is associated with chromosomal anomalies? What syndromes is it most commonly associated with?

cystic hygroma 50% Turner's Syndrome

used to describe herniation of the meninges and brain through the defect

encephalocele

teratoma located in the oropharynx

epignathus

enlargement of the thyroid gland

fetal goiter

congenital defect caused by an extra chromosome, which causes a deficiency in the forebrain; a range of abnormalities from abnormal cleavage of the forebrain

holoprosencephaly

congenital absence of the cerebral hemispheres because of an occlusion of the carotid arteries; midbrain structures are present, and fluid replaces cerebral tissue

hydranencephaly

ventriculomegaly in the neonate; abnormal accumulation of cerebrospinal fluid within the cerebral ventricles, resulting in compression and frequently destruction of brain tissue

hydrocephalus

abnormally wide-spaced orbits usually found in conjunction with congenital anomalies and mental retardation

hypertelerism

abnormally closely spaced orbits; association with holoprosencephaly, chromosomal, central nervous system disorders, and cleft palate

hypotelerism

Many of congenital malformations of CNS result from _______.

incomplete closure of neural tube

Describe the appearance of a complete bilateral cleft lip and palate.

large gap in upper lip on modified coronal view; nose is flattened and widened; a premaxillary mass may be present

Caudal displacement of cranial structures causes scalloping of frontal bones of skull, making fetal head resemble _____

lemon

spina bifida defect may occur anywhere along vertebral column but most commonly along _____ and _______ regions

lumbar and sacral regions

hypertrophied tongue

macroglossia

open spinal defect characterized by protrusion of the spinal meninges

meningocele

open spinal defect characterized by protrusion of the meninges and spinal cord through the defect, usually within a meningeal sac

meningomyelocele

abnormally small chin

micrognathia

underdevelopment of the middle structures of the face

midface hypoplasia

What is the best imaging plane to evaluate for cleft lip/palate? Which nationality has the highest occurrence of this anomaly? Unilaterals usually occur on which side?

modified coronal native americans left

Obstruction may be caused by ventricular defect like aqueductal stenosis; is referred to as ____ hydrocephalus

noncommunicating

increased thickness in the nuchal fold area in the back of the neck associate with trisomy 21

nuchal lucency

a cylindrical protuberance of the face that in cyclopia or ethmocephaly represents the nose

proboscis

If spina bifida defect is very large and severe, termed ______

rachischisis

Maternal diabetes, maternal obesity, hyperthermia, folic acid deficiency have been associated with ______.

spina bifida

neural tube defect of the spine in which the dorsal vertebrae fail to fuse together, allowing the protrusion of meninges and/or spinal cord through the defect; two types exist: spina bifida occulta (skin-covered defect of the spine without protrusion of meninges or cord) and spina bifida cystica (open spinal defect marked by a sac containing protruding meninges and/or cord)

spina bifida

open (non-skin-covered) neural tube defects, such as myelomeningocele and meningocele

spina bifida aperta

closed defect of the spine without protrusion of meninges or spinal cord; alpha-fetoprotein analysis will not defect these lesions

spina bifida occulta

Prosencephalon divides into____ and ____

telencephalon and diencephalon

solid tumor

teratoma

a rare arteriovenous malformation; the vein will be enlarged and will communicate with normal appearing arteries

vein of galen malformation