alveolar arch

That is the total length of the alveolar arch is smaller than the tooth arch (the combined mesiodistal width of each tooth).

In humans, the first space of the mouth is the mouth cavity, bounded laterally and anteriorly by the alveolar arches (containing the teeth), and posteriorly by the isthmus of the fauces.

The oral cavity proper is bounded laterally and in front by the alveolar arches with their contained teeth; behind, it communicates with the pharynx by a constricted aperture termed the isthmus faucium.