The workings of the pleats. When the pleats were sewn, the center back seam was left at the bottom with no other stitches to secure it from opening. Therefore, the pleats were lined last and the lining that covered the pleats was sewn in one piece, to make the center back seam secure.
The cuff is just an extention of the sleeve shape. It's sewn to the bottom of the sleeve, the join is covered with ribbed silk, and then it's folded up to create the cuff.