The standard shirt issued by the army since the 1830's, it bears the rectilinear body shapes in use since the 18th century. This shirt retains many design features which were outdated by the 1860's. Instead of cutting the garment to follow body contour, shapes were created by manipulating the grain.
Many subscribe to the myth that this, as well as other issue shirts were made in one size only. The basis of this assumption has been the Quartermaster's manual which gave rudimentary sizing in addition to a complete bill of materials. Subsequent documentation clearly shows that this shirt was made and issued in at least 3 sizes.