Some approx measures when the Jacket is flat unstretched
Armpit to Armpit: 20.5''
Lenght : Collar (taken from rear to Hem: 32.5''
Armpit to Cuff: 18''
Shoulders seam to shoulder seam (taken from rear): 18''
Consider as well that the girl in the picture is 52 kilos/ 8.18 stones and is tall 179 cm / 5.9 feet he usually wears a MEDIUM