Gupta et al identified several features in the limbs of a fetus which may indicate the presence of Down's syndrome. The authors are from St. Stephen's Hospital in Delhi, India.
Patient selection: mid second trimester onwards
Measurements taken during ultrasonography:
(2) upper arm
ratio of femur to tibia =
= (length of femur in mm) / (length of tibia in mm)
ratio of femur to tibia
1.1 (after 13 weeks gestation)
> 1.2 (after 20 weeks gestation)
tip of upper limb
to level of the pelvis
shorter than predicted
forearm (ulna and radius)
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Specialty: Obstetrics & Gynecology, Pedatrics, Genetics