The placket should open exactly halfway between the neck and the sternum, he said.
From the nytimes.com
When fastened with buttons, this opening is often called the placket front.
From the en.wikipedia.org
Cashmere-touch cardigan boasts a chunky ribbed collar, placket, hem and bright pink buttons.
From the independent.co.uk
A pen is clipped under the placket of his polo shirt.
From the delawareonline.com
This chambray shirt has a curved placket giving it an interesting edge in comparison to other denim shirts.
From the independent.co.uk
This type of cuff has four buttons and a short placket.
From the en.wikipedia.org
Dress shirts with a fly-front placket are also traditional.
From the en.wikipedia.org
His dress shirts come with contrasting patterns on the collar, under the cuffs and on the inside placket.
From the sfgate.com
Multiple buttons aligned perpendicular to the cuff hem, or parallel to the placket constitute a barrel cuff.
From the en.wikipedia.org
More examples
A piece of cloth sewn under an opening
A placket is an opening in the upper part of trousers or skirts, or at the neck or sleeve of a garment.Picken (1957), p. 254 Plackets are almost always used to allow clothing to be put on or removed easily, but are sometimes used purely as a design element. ...
A slit or other opening in an item of clothing, to allow access to pockets or fastenings
(Plackets) (Slits in apparel forming a closure). A small boxed area at the bottom of where the buttons are.
Fabric that surrounds and reinforces a closure in a garment
The piece of cloth that reinforces a split or opening in a garment; that usually also serves as the closure.
The part of a shirt or jacket where the garment fastens together.
Slit at neckline in a dress, blouse or skirt, usually reinforced with a fold of fabric.
A vertical slit extending from the front of a shirt's collar, often reinforced at the base to prevent tearing. Two or three buttons are usually placed within this placket area.