Journal of Ultrasound in Medicine, Vol 6, Issue 4 203-207, Copyright © 1987 by American Institute of Ultrasound in Medicine
Pitfalls in femur length measurements
R. B. Goldstein, R. A. Filly and G. Simpson
The following study was performed to determine the precise anatomic
correlate for the end points of sonographic measurement of the fetal femur.
A cadaveric fetal thigh was dissected in layers and correlated with
sonographic images. The margins of the osseous portion of the femur were
determined on sonograms. Potential for underestimating femur length
(oblique images) and overestimating femur length (including nonosseous
portions of the femur in measurement) can be eliminated by requiring a view
of the femur which includes the epiphyseal cartilages. In this way, the
margins of the osseous portion may be accurately estimated, and there is
assurance that the entire shaft has been visualized. Images of the
dissected specimen indicate that the "distal femur point," which may cause
confusion in measurement, is not a part of the osseous femur, but probably
represents a specular reflection from the lateral surface of the distal
epiphysis.
