Here are the measurements, taken with the garment laid flat. The hemline is partially elasticized, so I've given stretched and unstretched measurements.

Armpit-to-armpit: 19"
Hemline width (unstretched): 18"
Hemline width (moderately stretched): 21.5"
Length (front, center neck below collar to hem): 20"
Length (back, center neck below collar to hem): 25"

Please let me know if you need more information- thanks!