"gum ridge" refers to the area of raised tissue where your gums meet your teeth.
Full definition
Sometimes the frenulum can be attached to the back of the
lower gum ridge as well as the floor of the mouth.
The tongue tied baby also will be unable to protrude the tongue horizontally past
the gum ridge or lips, because of tension on the short or tight frenum in this posture.
Thus, accepting the solid food by opening the mouth widely enough to receive the spoon can be affected by a habit of inadequate mouth opening (see breastfeeding), the tongue may not protrude over
the gum ridge, instead it will hump at the back of the mouth and push the food out rather than draw it in.
A frenulum can be attached on the bottom side of the tongue anywhere from the base to the tip and is connected to the floor of the mouth anywhere from the base of the tongue to the top of baby's
gum ridge.
Sometimes a tongue - tie is obvious; the baby can clearly not stick her tongue over
her gum ridge or when she tries, the tight frenulum pulls her tongue into a heart shape.
The baby must be able to extend her tongue past
her gum ridge and cup the breast.