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Femur length (obstetric ultrasound)

Last revised by Dr Jeremy Jones ◉ on 20 Sep 2021

Citation, DOI & article data

Citation:

Stanislavsky, A., Jones, J. Femur length (obstetric ultrasound). Reference article, Radiopaedia.org. (accessed on 18 Aug 2022) https://doi.org/10.53347/rID-26433

DOI:

https://doi.org/10.53347/rID-26433

Permalink:

https://radiopaedia.org/articles/26433

rID:

26433

Article created:

21 Dec 2013 by Dr Alexandra Stanislavsky ◉

Revisions:

11 times by 5 users - see full revision history

System:

Obstetrics

Section:

Approach

Tags:

cases, stub

Synonyms:

Femur length
Femur diaphysis length
Femoral lengths
Femoral length
Femur length (FL)

Fetal femur length (FL) is one of the basic biometric parameters used to assess fetal size. Femur length together with biparietal diameter, head circumference, and abdominal circumference are computed to produce an estimate of fetal weight. In the second trimester, this may be extrapolated to an estimate of gestational age and an estimated due date (EDD).

Femur length can be used to calculate fetal length, another predictor of fetal growth, with the following equation ³:

Fetal length in centimeters = 6.18 + 0.59 x femur length in millimeters.