The model is 5'9" and wearing size S
The Short Sleeve Shirt in stretch cotton is true to size, though it will be a slimming, not-boxy fit.
XS - Back Length 27, Chest 17, Sleeve Length 9, Arm Opening 12
S - Back Length 27.5, Chest 18, Sleeve Length 9.5, Arm Opening 12.5
M - Back Length 28, Chest 19, Sleeve Length 10, Arm Opening 13
L - Back Length 28.5, Chest 20, Sleeve Length 10, Arm Opening 13.5
XL - Back Length 29, Chest 21, Sleeve Length 10.5, Arm Opening 14
XXL - Back Length 29.5, Chest 23, Sleeve Length 11, Arm Opening 14.5