The semi-raglan sleeve has an armhole that curves to the middle of the shoulder seam. The more commonly recognized raglan seam goes all the way to the intersection of the shoulder and the neckline. One of the most common items of clothing that employs the semi-raglan sleeve is the baseball shirt.
What makes semi-raglan sleeves so unique is their distinguishing slanting seam. This type of sleeve has no seam at the defined shoulder. The manor in which the seam is placed makes it appear as if there is not a specific defining line of shoulder placement within the garment.
This type of sleeve was named after Field Marshal FitzRoy James Henry Somerset, 1st Baron Raglan. The renowned field marshal lost his arm at the battle of Waterloo. A sleeve was designed to fit his coat and accommodate the loss of his arm. Ironically, sleeves are considered arm covers, but the raglan type sleeve was created for the sole reason that the Baron of Raglan needed a garment to accommodate the loss of his arm.
While regular sleeves commonly range in length, the semi-raglan and raglan sleeves tend to be designed in a half or three-quarter length. This length goes back to the the purpose for which the sleeved was created. Regardless of the length, these types of sleeves are often fuller under the arm.
Providing a more casual look, the semi-raglan sleeve is often used in athletic wear. With the sleeve crafted from one piece of material, greater range of motion is afforded those wearing it. Traditionally, garments with semi-raglan sleeves are made in stretch and jersey materials. For this reason, the baseball shirt is also referred to as a raglan tee.
These types of sleeves are also employed in the design of coats. Coats with the semi-raglan sleeve are made in many different fabrics, including cashmere and wool; Spring coats with this style are often made of cotton. Any outerwear garment that has a raglan type sleeve is often referred to as a raglan. The sleeves are also common for plus size designs and for maternity wear, as they tend to be roomier.
The semi-raglan sleeve is a popular starter sleeve for those learning to both sew and knit. The reason for this is that it is easy to attach to the main part of the garment. Following a pattern for raglan sleeves also is less exacting, leaving more room for error.