The two-piece sleeve is a sleeve fashioned from two pieces of material instead of the more traditional approach that employs only one piece. The purpose of this type of sleeve is to allow for a greater range of bending motion at the elbow. Often the two-piece sleeve is chosen when a more tailored appearance is desired.
Sleeves have a tendency to wrinkle, specifically at the elbow area. The two-piece sleeve offers less wrinkling than its one-piece counterpart. The reason is that by using two pieces of material, a slight L-shape is created, similar to the bend of the elbow and mimicking the way an arm is naturally held.
While the natural shape of the arm at first seems to be cylindrical, in reality it is not. Even in a completely relaxed state, the arm has a slight natural bend. With the slight bend at the elbow, the front of the arm is naturally shorter than the back of the arm. For this reason the back portion of a sleeve needs to be slightly longer than the front, to fit the true proportions of the arm.
The two-piece sleeve has seams which appear at both the front and the back of the arm. The under section of the sleeve will actually be a tad bit smaller than the upper part of the sleeve. This will, in effect, make the seam appear less noticeable on the finished garment.
The seams of the two-piece sleeve also fall slightly off center from the front and back of the arm. With the seams falling in the offset places, they are then less apparent when the apparel is worn. This strategic placement of the seams allows for greater range of motion as well.
The two-piece sleeve is traditionally used in full sleeves and three-quarter length sleeves, as opposed to the half length sleeve. This is because there is no need for a bend in the elbow in the shorter sleeve. The single-piece sleeve also is much easier to make, so most patterns will follow this premise for the shorter sleeve.
The designs for jackets tend to use the two-piece technique even more so than shirts and blouses. Jackets necessitate even greater motion, as another garment is usually worn underneath them. Whatever the type of long-sleeved clothing worn, the two-piece sleeve offers those wearing it a graceful, tailored fit.