A warm welcome to the DINED User Forum.
I have no knowledge of widespread use of elliptical body measurements in anthropometry. I can however imagine that fitting of an ellipse to certain body sections would make sense as a simplified representation. Personally, in a project on ear anthropometry, I used ellipse fitting to quantify the differences in ear canal cross section between Asian and Western population (not published). Here you can find another study where ellipses were used to quantify abdominal visceral compartment area:
He, Q., Engelson, E. S., Wang, J., Kenya, S., Ionescu, G., Heymsfield, S. B., & Kotler, D. P. (2004). Validation of an elliptical anthropometric model to estimate visceral compartment area. Obesity research , 12 (2), 250-257.
The measure you are referring to would be a quarter of an ellipse? It could sure be useful. How would you report the elliptical measurement? Via the semi axis lengths? In that case, it should also be defined how the ellipse is aligned with respect to the body.