Assessment of the Second Trimester

Question 1

fetal circulation

Answer 1

• umbilical vein
• ductus venosum to right atrium
• foramen ovale
• left atrium to left ventricle
• aorta
• approx half the blood leaves through umbilical arteries and back to placenta for reoxygenation

Question 2

dolichocephalic

Answer 2

elongated shape to the fetal cranium; cephalic index < 70%. commonly associated with breech fetal presentation

Question 3

circumvallate placenta

Answer 3

condition in which the chorionic plate of the placenta is smaller than the basal plate, the margin has a rolled edge

Question 4

coronal view of facial structures useful for visualizing what?

Answer 4

• orbital rings
• maxilla
• mandible
• nasal septum
• parietal bones
• zygomatic bones

Question 5

brachycephalic

Answer 5

round shape to the fetal cranium; cephalic index 85%. commonly associated with cephalic fetal presentation

Question 6

cephalic index

Answer 6

a ratio of the cranium derived to determine the normality of the fetap head shape

Question 7

circummarginate placenta

Answer 7

condition in which the chorionic plate of the placenta is smaller than the basal plate, with a flat interface between the fetal membranes and the placenta

Question 8

cervical os

Answer 8

• length of cervix determines competence
• length is measured between the internal and external cervical os
• normal length varies between 2.5 and 4 cm

Question 9

alpha fetoprotein

Answer 9

• produced by the fetus
• found in the amniotic fluid and maternal serum
• normal values vary with gestational age

Question 10

causes of low alpha fetoprotein

Answer 10

• overestimated gestational age; fetus younger than expected
• chromosomal abnormalities
• trophoblastic disease
• long standing fetal demise
• chronic maternal hypertension or diabetes

Question 11

sagittal view of facial structures is useful in determining?

Answer 11

• relationship of the nose and lips
• frontal bossing
• chin formation

Question 12

tentorium

Answer 12

“tent” structure in the posterior fossa that separates the cerebellum from the cerebrum

Question 13

vermis cerebelli

Answer 13

narrow median part of the cerebellum between the two lateral hemispheres

Question 14

choriod plexus

Answer 14

• echogenic cluster of cells
• important in the production of cerebrospinal fluid
• not located in the anterior or occipital horns
• choroid plexus cyst will normally regress by 23 wks

Question 15

cavum septi pellucidi

Answer 15

• presence excludes almost every subtle midline brain malformation
• filled with cerebrospinal fluid
• found at the level of the BPD
• located inferior to the anterior horns of the lateral ventricles
• closes by 2 yrs of age

Question 16

when does the visualization of the gallbladder peak?

Answer 16

20-32 gestational weeks

Question 17

causes of high alpha fetoprotein

Answer 17

• underestimated gestational age; fetus older tha expected
• multiple gestations
• open neural tube defect
• cystic hygroma
• renal anomalies
• fetal demise

Question 18

meconium

Answer 18

a material that collects in the intertines of the fetus and forms the first stool of a newborn

Question 19

when is the spine ossified?

Answer 19

18 weeks