It is said that there are only two sizes of clothing issued in the Army: Too Big and Too Small.
Technically, each pair of pants and each shirt are issued according to a range of “one size fits all” within three categories: Small, Medium, and Large. From there, you can get “Small-Regular” or “Medium-Large” or “Large-Short” and other combinations of Small, Medium, and Large mixed with Short, Regular, and Large. So, a very small male soldier or petite female would end up with a Small-Short set, for example. Most people of average size get Medium-Regular sets, and so on.
If I remember correctly, I think there is a separate category for “Large-Tall”, too, for the tall, skinny folks who cannot wear a “Large-Large”. Large-Large is more suitable to the folks who are just plain big folks (think “built like a Slavic plowhorse”) or who have gotten portly. Either way, for the most part everyone in the Army tends to end up with uniforms that “more or less fit”. Patterson’s uniforms fit perfectly, so his only logical deductions is that he must have suffered hideous deformities at birth which are only now becoming manifest.
The only place where efforts are made to offer a wide range of sizes tends to be in hats and boots. There’s also dress uniforms, the fancy, colorful uniforms with all the shiny stuff on it for ceremonial occasions. Those tend to be better-fitted as well, since they are worn for dress-to-impress events and can’t be too baggy or tight. When in Basic Training, they waited until near the end of the training cycle to measure us for dress uniforms, in case someone washed out of training– making their dress uniform measurements unnecessary.