Normal 2nd & 3rd TM Flashcards
Landmarks of the spine
Cervical- neck Thoracic- heart Lumbar-kidneys Sacral- bladder or femur Identified in most pregnancies by 16 weeks
Nagele’s Rule
EDC= LMP-3months+ 7 days
To calc due date
Femur length
Most commonly measured bone.from greater trochanter to femoral condyles. Hyperechoic linear structures represents ossified portion of the femoral diaphysis. Measure shaft of femur. Predictor of GA & indicator of skeletal dysplasias & asymmetric growth retardation. 10 1/2 weeks ossification center of femur (1mm)
Humerus
Identified by imaging fetal spine in upper thoracic-lower cervical region, identify scapula then rotate.
Ulna & radius
Ulna is the Larger of the 2 bones and Longer then the radius. Lower end is slender. Both hyperechoic shaft meet at the wrist where no ossified hypechoic carpel bones are located
Tibia & Fibula
Tibia in the front fibula behind. Tibia is the longer and thicker. Lower end of the tibia articulates with one of the tarsals to form the ankle joint.
Fetal heart
2 ventricles 2 Atriums. RV is the most anterior chamber. Descending aorta is immediately anterior and slightly to the left of the spine. LA is anterior to the aorta. Inter ventricular septum is the echo genie line btw RV & LV. Former ovals is seen btw LA & RA. 120-180 BPM average. Atria & Ventricle 1:1. Apex points left when spine at 6:00
Stomach
Should be seen by 14-16 weeks. LUQ. Fetus swallows AF at 16 weeks. AF volume reaches about 400-500 ml.
Kidneys
Seen around 15-16 weeks. Visualization becomes consistent by 20 weeks. AP diameter should be less than 5 mm. Circumference about 1/3 size of abdomen (.27-.30) PF=peri euphoric fat P=pyramids A=adrenal
Bladder
Can be seen by 15 weeks. Fills every 30-45 mins. Wall should be thin. Ureter <1mm.
Umbilical Cord Insertion
Connects fetus to placenta. Goes into liver and heart. 2 arteries and 1 vein. Arteries go on either side of the bladder.
Liver
10% of weight at 11 weeks. 5% of weight at full term.
GB
Normally seen at 20 weeks. Located to the right of the portal vein
Small Bowel
Seen after 27 weeks, seen more in the center
Colon
Seen near the end if the 2nd TM. Hypechoic area around outer wall is normal it’s not fluid it’s muscle.
ABD abdominal diameter
Average of 2 diameters. 1st from spine to anterior abd wall. 2nd perp to 1 st measurement.
ABD= 2(3.14)r. ABD=(3.14)d
BPD
Leading edge to leading edge. Midbrain: falx, cavum septi pellucidi, & thalamus. Not as accurate of measurement in 3 rd TM. Always just check lateral ventricles, they are superior to BPD
Cephalic Index
BPD/OFD(100)
BPD is always smaller
Occipito Frontal Diameter (OFD)
Front to back measurement. Done at the same level as BPD, but measures outer to outer. Determines if baby’s head is shaped the right way.
Brachiocephalic
Round head
Dolichocephalic
Elongated head
Area corrected BPD (BPDa)
BPDa= the square root of (BPDxFOD)/1.265 (BPD+FOD/2)(3.14) = (BPD+FOD) x 1.57
Cerebellum
Start at BPD and angle back part of probe posterior. Cerebellum is in the back of the head. If really small it could be herniated
AC
AC=2(3.14)r
R=radius(diameter divided by 2)
Preterm
Born before 37th week. The earlier their born the less developed the organs are
Preeclampsia
Mother gets high blood pressure which compromises flow to fetus
Mean Gestational Age
Mean gestational age= GA (today) + GA (prior)= #/2= MGA
Interval Growth
BPD (today) - BPD (last) = growth mm/wk
