Here is a classic vintage long sleeve button down western snap shirt by Bon Homme. Sharp looking plaid in brown, white, maroon, yellow, and black. Seven button front, two on each cuff. Thin, light weight, and fairly sheer. It's in amazing shape with tons of life left. The tag says Medium 15 - 15 1/2, but here are the measurements. (refer to the last pic above to see how I measure shirts)

Chest (armpit to armpit) 19"
Shoulder to end of sleeve (including cuff) 25"
Length 30"

This item is sold from a vintage boutique in Roanoke, VA.