The Bichat adipose bag is an accumulation of fat located between the masseter muscle and the buccinator muscle, on both sides of the face. These two muscles that allow the chewing movements need a lubricating grease pad which is the bichat bag. Although all people have them, in some cases these fat bags develop in an exaggerated way resulting in a face that is too round and bulging. It becomes necessary to make a thinning by reducing the bags of bichat. This is done by a small incision inside the mouth.

The volume of this fat is not necessarily related to the body weight, and that is why many thin people can present an extended and thick face that does not correspond to their body weight