Parts of a Bra
A bra has many components, depending on the variety. For an underwire bra, there are adjustable straps, two cups, a closure and two molded metal bust supports. In a soft-cup or triangle bra, there are the same parts minus the metal bust boning.
In addition to these parts, specialty foundations may have other pieces. A padded bra might have pillow-like inserts, for instance. Or, a strapless bra may be stitched with pieces of sticky silicone tape to reduce slippage.
Form and Function
The prime purpose for a bra is to support the bust so that breast skin doesn't stretch over time--the prime cause for a sagging bust. The bra adds lift and negates the force of gravity.
Underwire bras are more popular because of the amount of support they afford. Think about a purse, for instance. Many people like a purse that has a supported bottom because the structure is more solid. Some choose a soft variation, but not as many. The small bit of metal distributes the mass of the bust evenly over the entire structure of the garment. This is extremely important for those with a larger bust.
Bra technology has advanced to include bras for bigger busts that don't have underwires. For women who find metal parts painful or uncomfortable, there are bras that have plastic bones or strong tapes for reinforcement. However, these bras require extra fabric to distribute breast tissue weight evenly.
How Cups Work
The different cup shapes mold the bust into a certain form. The shape and roundness of a cup is determined by the pattern form and size. A more circular, short pattern piece will produce a demi-cup, which crafts a globular line. The longer, teardrop-shaped full-coverage cup flattens and spreads weight over a larger surface area.
For day-to-day wear, a full cup will probably be the most comfortable option. Save the demi cups for weekends and special occasions unless you wear an A or B cup.
A Few Words on Fit
To position the bra correctly, the straps must be adjusted to the proper length. The back panels of the bra should lie evenly on the horizontal, as should the front. Look in a mirror while trying on a bra, making certain to focus on pulling or discomfort when the arms are at the sides.
Get the right band size. Measure the underbust with a tape, or have a professional fitting. Underbust fit is crucial to bra comfort, or else the garment will chafe and shift with use. If necessary, get a bra strap extender to increase comfort.
Buy underwear made of good fabrics and materials. Cheap undies may look fun and appealing, but the fabric will stretch over time and stop being as supportive.