OB - Fetal Biometry (with solved solutions)
gestational sac diameter correct answers measure at 5weeks
measure three planes, then average
measure inner to inner
greater than 8mm - should see yolk sac
greater than 16mm - should see embryo
crown rump length correct answers most accurate method of determining GA
measure form top of head to rump; exclude legs
should see heartbeat when measures greater than 7mm
cannon get accurate measurement after 12-13 weeks
embryonic heart rate correct answers acceleration from 5 to 9 weeks correlates with GA
greater than one week behind CRL age associated with first trimester loss and should be
followed
obtain accurate measurement by magnifying image and suing fast sweep m mode
biparietal diameter correct answers accuracy decreased throughout pregnagny
measure outer to inner edge
landmarks = thalami, CSP, midline falx, oval head
growth adjusted sonar age
growth adjusted sonar age correct answers categorizes fetuses in small, average, or large growth
categories to accommodate for biological variance in BPD size
brachycephaly correct answers basketball head
dolicocephaly correct answers egghead
oxycephaly correct answers elevated cranial vault
head circumference correct answers assesses fetal age without influence by head shape
measure outer perimeter of skull at the level of the BPD
calipers from front to back
cephalic index correct answers ratio of BPD to OFC to evaluate for normal head shape
normal rage is 75-85%
ventral cranial diameter correct answers measure triangle at coronal view
normal headshape will have equilateral triangle
abdominal circumference correct answers better for evaluating fetal growth than for determine
fetal age
measure at the level of the liver, stomach, and umbilical vein intersection with portal vein
gestational sac diameter correct answers measure at 5weeks
measure three planes, then average
measure inner to inner
greater than 8mm - should see yolk sac
greater than 16mm - should see embryo
crown rump length correct answers most accurate method of determining GA
measure form top of head to rump; exclude legs
should see heartbeat when measures greater than 7mm
cannon get accurate measurement after 12-13 weeks
embryonic heart rate correct answers acceleration from 5 to 9 weeks correlates with GA
greater than one week behind CRL age associated with first trimester loss and should be
followed
obtain accurate measurement by magnifying image and suing fast sweep m mode
biparietal diameter correct answers accuracy decreased throughout pregnagny
measure outer to inner edge
landmarks = thalami, CSP, midline falx, oval head
growth adjusted sonar age
growth adjusted sonar age correct answers categorizes fetuses in small, average, or large growth
categories to accommodate for biological variance in BPD size
brachycephaly correct answers basketball head
dolicocephaly correct answers egghead
oxycephaly correct answers elevated cranial vault
head circumference correct answers assesses fetal age without influence by head shape
measure outer perimeter of skull at the level of the BPD
calipers from front to back
cephalic index correct answers ratio of BPD to OFC to evaluate for normal head shape
normal rage is 75-85%
ventral cranial diameter correct answers measure triangle at coronal view
normal headshape will have equilateral triangle
abdominal circumference correct answers better for evaluating fetal growth than for determine
fetal age
measure at the level of the liver, stomach, and umbilical vein intersection with portal vein
