A cap sleeve is more of a decorative detail than a true sleeve - but it's a great-looking addition to what would otherwise be a simple arm-baring top.
Like its name implies, this sleeve consists of little more than the cap itself, and generally doesn't go all the way around the armhole.
As a shoulder detail, it adds a bit of interest and coverage when you want something just a bit more than sleeveless, but less than a typical short sleeve.
And it's easy to draft and to sew!
Then mark a point on the grainline about 1 1/2" to 2" above the bicep line. From there, draw a gentle curve to each side of the cap, below the notches (the ends will be about 3/4" above the bicep line). This is your hemline.
The end result is a very short sleeve, which does not surround the arm. Be sure to mark where the sleeve ends on the front and back blouse pieces!
For a very casual top, you could turn and stitch the hem, but this sleeve looks best with a hem facing. The facing should be applied before setting the sleeve into the armhole.
And don't forget to finish your pattern with seam allowances, hem allowance, facings - or whatever is required of your style.
ClothingPatterns101.com does not sell the personal information of its users to anyone, ever.