Set-in sleeve

The set-in sleeve is the most classic and most common sleeve construction. The sleeve is cut as its own pattern piece and attached to the armhole of front and back panels with a round seam. The seam follows the natural shoulder–arm boundary and sits at the transition from shoulder to upper arm.

The construction requires precise sewing: the sleeve cap is worked with a little ease so that it sits cleanly into the curved armhole. This ease provides the slight elevation at the shoulder point and the crisp shoulder line typical of set-in sleeves. On high-quality jackets it is additionally emphasised with wadding or sleeve-head roll.

The set-in sleeve is the standard on shirts, jackets, coats and most blazers. It produces a clearly defined, tidy silhouette and is mandatory on formal wear. For active sportswear or performance shirts it is often replaced by raglan or related constructions because it restricts freedom of movement in the armhole area.

Compared to the raglan the set-in sleeve looks more formal and structured but restricts shoulder mobility more.