CHAPTER 51-53

During an ultrasound exam, the fetus is noted to be lying perpendicular to the maternal spine. What is the fetal lie?

Transverse

During an ultrasound exam, the fetal head is visualized in the lower uterine segment just above the symphysis pubis. Which presentation is this?

Vertex (cephalic)

The fetus is noted to have its head toward the uterine fundus, with the buttocks closest to the cervix. This describes:

Breech

Ultrasound shows the femurs flexed at the hips, with the lower legs extended upward toward the fetal face. This is:

Frank breech

Which breech presentation is characterized by both hips and knees flexed?

Complete breech

A fetus demonstrates one foot presenting closest to the cervix on ultrasound. What is the presentation?

Footling breech

Which sonographic finding is most consistent with a breech presentation?

Buttocks or lower extremities in the lower uterine segment

Which breech presentation is most associated with the need for cesarean delivery?

Complete breech

On ultrasound, the fetal head is located in the uterine fundus while the lower extremities are visualized near the cervix. This most likely represents:

Breech presentation

Which breech presentation is most commonly considered safe for external cephalic version to facilitate vaginal delivery?

Frank breech

In a third-trimester breech presentation, the fetal head is most likely to appear:

Elongated and dolichocephalic

When documenting a fetus in transverse lie, which of the following should be reported?

Position of fetal head (right or left) and spine orientation

When a fetus is in an oblique lie, what is the MOST appropriate method of documentation?

Report which quadrant contains the head and the direction of the spine

On a normal fetal situs exam, the stomach should be visualized on which side?

Left

Which structure is normally located on the fetal RIGHT side?

Gallbladder

The cardiac apex in a normal fetus should point toward which side?

Left

During a transverse scan of the fetal abdomen, the aorta is identified. Where should it be located?

Left of midline, anterior to spine

Which statement correctly describes the location of the inferior vena cava (IVC)?

Right of midline, slightly anterior to the aorta

The cerebellum is best evaluated in which scan plane?

Axial posterior fossa angled inferior from BPD plane

What is the normal sonographic appearance of the fetal cerebellum?

Dumbbell-shaped structure with two hemispheres

The “banana sign” is associated with which condition?

Chiari II malformation

The choroid plexus is best visualized in which plane?

Axial at level of lateral ventricles

What is the normal sonographic appearance of the choroid plexus?

Echogenic butterfly pattern

The “dangling choroid plexus” sign indicates:

Ventriculomegaly

The cisterna magna is located:

Posterior to the cerebellum

What is the normal measurement range of the cisterna magna?

3–11 mm

Obliteration of the cisterna magna is associated with:

Chiari II malformation

The lateral cerebral ventricles are evaluated in which plane?

Axial at atrial level

What measurement defines ventriculomegaly?

≥ 10 mm

The midline falx appears as:

Two linear echogenic lines dividing hemispheres

Absence of the midline falx suggests:

Holoprosencephaly

The cavum septi pellucidi (CSP) is best visualized:

At BPD level anterior to thalamus

Absence of the CSP is most strongly associated with:

Agenesis of corpus callosum

At the level above the lateral ventricles, two linear echogenic structures are seen lateral and parallel to the falx. These represent:

White-matter tracts

White-matter tracts are located:

At the level of the lateral ventricles

The MOST important structure used to assess ventriculomegaly at the atrial level is:

Choroid plexus (glomus)

At the atrial level, the choroid plexus should normally appear:

Filling the ventricle completely

A “floating” or “dangling” choroid plexus most strongly indicates:

Ventriculomegaly

Which structure is located at the BPD (widest diameter) level?

CSP, thalami, corpus callosum; frontal horns

At the BPD level, the thalami appear:

Heart-shaped

The apex of the thalami heart shape points toward the fetal:

Occiput

Which structure is NOT part of the posterior fossa level?

CSP

Cisterna magna measurement is taken from:

Vermis to occipital bone inner table

Which structure is highly pulsatile at the cerebral peduncle level?

Circle of Willis

At the cerebral peduncle level, the Circle of Willis appears:

Triangular

Which structure separates the anterior and middle cranial fossae?

V-shaped sphenoid

The skull base includes:

Anterior, middle, and posterior fossae

The choroid plexus primarily produces:

CSF

CSF flows from the lateral ventricle to the third ventricle through the:

Foramen of Monro

The nuchal fold scan plane includes:

CSP, cerebellum, and cisterna magna

A nuchal fold measurement >6 mm is MOST associated with:

Trisomy 21

Normal nuchal fold measurement up to 20 weeks is:

≤ 5 mm

Normal fetal brain parenchyma appears:

Hypoechoic

The hypoechoic appearance of fetal brain tissue is due to:

High water content and small reflectors

Which structures are evaluated in the fetal profile (sagittal) view?

Frontal bone, nasal bone, lips, chin

Which abnormality can be detected in the sagittal facial profile view?

Micrognathia

Which condition CANNOT be reliably excluded in the profile view?

Cleft soft palate

Which structures are assessed in the coronal facial view?

Upper lip, orbits, lens, nasal septum, maxilla, palate (limited), zygomatic bone, mandible

Which abnormality is best detected in the coronal face view?

Cleft lip

Coronal facial view is used to assess:

Hyper/hypotelorism

Which structures are seen at the transverse orbital level?

Orbital rings, IOD, OOD/BD

Which condition is excluded at the orbital level?

Anophthalmia

Absent nasal bone is associated with ALL EXCEPT:

Turner syndrome (Monosomy X)

Absent nasal bone is found in approximately:

25–33% of Down syndrome fetuses

Normal fetuses show:

Present nasal bone

Macroglossia is associated with:

Beckwith-Wiedemann syndrome and aneuploidies

IOD is measured as:

Inner orbit to inner orbit

OOD is measured as:

Outer orbit to outer orbit

Frontal bossing is associated with:

Skeletal dysplasia

Frontal slanting is associated with:

Microcephaly

Cleft lip is best ruled out in:

Coronal view

Which one of the following structures carries oxygenated blood from the umbilical vein to the inferior vena cava (IVC)?

Ductus venosus

Which one of the following terms indicates that the fetal head is toward the fundus of the uterus?

Breech

At what gestational week does the volume of amniotic fluid stop increasing?

34th

Which one of the following indicates that the liver is on the right, the stomach is on the left, and the heart apex is on the left?

Normal situs

The widest transverse diameter of the skull and the proper level to measure the biparietal diameter (BPD) includes which one of the following structures?

Thalamus

The three vessels found in the umbilical cord are which of the following?

Two arteries and one vein

Normally, the fetal bladder empties at least every ______

60 minutes

Because of the low-density brain tissue, the texture of the brain may appear ___

Hypoechoic

The cavum septum pellucidi is observed anterior to the ____

Thalamus

The profile view of the fetal face is important to examine to rule out all of the following abnormalities except:

Cleft soft palate

Fetal anatomy may be assessed accurately after ____

18 menstrual weeks

In the transverse plane, an abnormal fetal spine may appear splayed in all of the following configurations except:

Y shaped

When evaluating the fetal spine, aligning the transducer is an ______ axis to the spinal element is important

Perpendicular

Which one of the following structures shunts blood away from the lungs?

Ductus arteriosus

Dilation of the entire ventricular system, including the fourth ventricle, is associated with which one of the following abnormalities?

Spinal defects

In the sagittal scan of the vertebral column, the normal appearance is:

Two curvilinear lines forming a “railway sign”

The “railway sign” in the sagittal plane is produced by:

Posterior and anterior laminae and spinal cord

In the sagittal plane, an abnormal spinal defect is indicated by:

Discontinuity of parallel lines

Loss of which feature accompanies sagittal spinal defects?

Posterior skin border

In the coronal scan, the normal vertebral column shows:

Two parallel columns

In the coronal plane, spinal defects are identified by:

Splaying or widening of parallel lines

Which scan plane is most important for detecting spinal defects?

Transverse

In the transverse plane, a normal closed neural tube is indicated by:

Three equidistant echoes forming a circle or triangle

In the transverse plane, an open neural tube defect is suggested by:

Pedicles splayed in V-, C-, or U-shape

For accurate spinal assessment, the transducer must be:

Perpendicular to spinal elements

The three ossification points of a vertebra include all EXCEPT:

Spinous process

In open spina bifida (meningomyelocele), the skin integrity is:

Absent

In fetuses with open neural tube defects, the membrane overlying the defect is:

Absent

During evaluation, what must be confirmed in each spinal segment?

Skin integrity