English to French Medical Medical (general) chirurgie esthétique

On réalise un abdominoplastie :

"We’re then going to make an incision that’s gonna be a low placed incision from hipbone to hipbone. We’re also gonna make a small incision around her navel and when we do this we will be able to elevate her abdominal wall skin and fat exposing her ***six pack muscles*** which are separated. I’m gonna bring those muscles back together surgically and really tighten things up as much as I can. We’re gonna then remove excess skin and fat, and we’re going to close everything meticulously."

Et plus loin :

"An incision that we are going to make. We’re making our way down to the ***six-pack muscles*** and the tissue that covers those muscles. This is adipose tissue or fat. So now we are just raising the abdominal wall skin off of the ***six-pack muscle***"

"The ***six-pack muscles*** give the stomach its shape."

Qu'est-ce que ces six muscles ? Le muscle grand droit ? Mais pourquoi six ?

Merci de m'éclairer sur ces muscles et bonne journée à tous !