Human fetal extremity lengths in the interval from 9 to 21 menstrual weeks of pregnancy
Related Experiment Video
Updated: Aug 11, 2026

Fetal Echocardiography and Pulsed-wave Doppler Ultrasound in a Rabbit Model of Intrauterine Growth Restriction
Published on: June 29, 2013
Abstract:
Fetal arm, leg, and foot lengths were freshly measured with vernier calipers on all fetuses aborted by me from 1975 to 1983. With the use of these measurements from the 575 patients with reliable menstrual or conception dates and uterine size in agreement (+/- 2 weeks) with dates, statistical analyses were performed to determine the polynomial regressions of menstrual weeks of pregnancy for each extremity length. The data best fit the following formulas, where W represents weeks and F, L, and A are foot, leg, and arm lengths in centimeters: W = 3.03 + 17.4(F) - 10.8 (F2) + 3.36(F3) - 0.367(F4); W = 5.74 + 6.49(L) - 1.90(L2) + 0.305(L3) - 0.0161(L4); W = 5.19 + 5.65(A) - 1.45(A2) + 0.203(A3) - 0.00934(A4). Mean foot lengths at each week agreed well with those of Streeter, and when corrected for bias, all foot lengths were in near perfect agreement with his data.
Related Concept Videos
Bone Formation by Intramembranous Ossification
The process begins when mesenchymal cells in the embryonic skeleton gather together and differentiate into osteogenic cells, which then develop into...
Bones of the Upper Limb: Humerus
Changes in the Appendicular Skeleton with Age
Initially, the limb buds consist of a core of mesenchyme covered by a layer of ectoderm. The ectoderm at the end of the limb bud thickens to form a narrow crest called the apical ectodermal ridge. This ridge stimulates the underlying...
Development of the Heart
As the embryo undergoes lateral folding, these paired tubes approach each other, merging into a single primitive heart tube by...
Fetal Circulation
Two umbilical arteries transport blood from the fetus to the placenta. At the placenta, the blood absorbs oxygen and nutrients while simultaneously eliminating waste products. This oxygen-enriched and nutrient-rich blood then returns to the fetus through one...
Development of the Sexual Organs in the Embryo and Fetus
Near the gonadal ridges, two duct systems are present: the mesonephric ducts (Wolffian ducts) and paramesonephric ducts (Müllerian ducts). These ducts form the basis for the male...

