Looks as if your are trying to do the jacket as one shape so it wont close? If I was doing this drawing I would do one side only, then make a copy of that and then use the Transform and reflect the shape vertically. do the same for the back but maybe after using transform you could use the Pathfinder to join both sides, it would depend if you wanted a seam down the back. all the sleves could be done the same way.