Commin Measurment Techniques In OB/GYN Sonography

Question 1

Abdominal circumference (AC)

Answer 1

Caliper placement
Ellipse around abdomen ( including subcutaneous fat and skull )

Question 2

Biparietal diameter (BPD)

Answer 2

Caliper placement
Outer skull - to- inner skull (leading edge - to- leading edge)

Question 3

Cephalic index (CI)

Answer 3

Caliper placement
Biparietal Diameter (BPD) / Occipital Frontal Diameter (OFD)

Question 4

Normal Cephalic Index

Answer 4

0.70-0.86 (70%-80%)

Question 5

Cerebellum

Answer 5

Caliper placement
Lateral edge -to- lateral edge (transverse)

Question 6

Cervical length

Answer 6

Caliper placement
Internal os -to- External os / where anterior and posterior cervical walls touch

Question 7

Cisterna magna

Answer 7

Caliper placement
Posterior cerebellum -to- inner occipital bone AP

Question 8

Crown rump length (CRL)

Answer 8

Caliper placement
Crown -to-Rump of embryo

Question 9

Endometrium

Answer 9

Caliper placement
Outer basalis -to- outer basalis; AP measurement in Sagittal scanning plane

Question 10

Endometrium ( with fluid in cavity )

Answer 10

Caliper placement
Measure anterior and posterior endo/ add together

Question 11

Femur length (FL)

Answer 11

Caliper placement
Edge- to- Edge of Ossified diaphysis ( midpoint of slant distal third trimester)

Question 12

Fibula

Answer 12

Caliper placement
End-to- End

Question 13

Gestational Sac (GS)

Answer 13

Caliper placement
Inner-to- inner

Question 14

Head circumference (HC)

Answer 14

Caliper placement
Ellipse around outer skull margin ( no skin/scalp included )

Question 15

Humerus (HL)

Answer 15

Caliper placement
End-to-end

Question 16

Lateral ventricular arterial width (LVAW)

Answer 16

Caliper placement
Inner-to-inner at level of the glomus of the choroid plexus

Question 17

Nasal bone (NB)

Answer 17

Caliper placement
Edge-to-edge on midsagittal view (transducer 45 degrees to fetal profile)

Question 18

Nuchal fold (NF)

Answer 18

Caliper placement
Outer occipital bone- to- outer skin

Question 19

Nuchal translucency (NT)

Answer 19

Caliper placement
Inner edge-to-inner edge (“on to on”)

Question 20

Occipital- frontal diameter (OFD)

Answer 20

Caliper placement
Outer skull posteriorly -to- outer skull anteriorly

Question 21

Outer orbital diameter (OOD)

Answer 21

Caliper placement
Outer edge of orbit -to- outer edge of contralateral orbit

Question 22

Ovarian volume

Answer 22

Caliper placement
Length x width x height x 0.523

Question 23

Placental thickness

Answer 23

Caliper placement
Anterior to posterior

Question 24

Rental pelvis

Answer 24

Caliper placement
Anterior to posterior

Question 25

Tibia

Answer 25

Caliper placement
End to end

Question 26

Thoracic circumference

Answer 26

Caliper placement
Ellipse around bony thorax (no skin included)

Question 27

Yolk sac

Answer 27

Caliper placement
Inner to inner