this is defined as any mucous membrane of the mouth - including palate, lips, uvula, etc. ncit split mouth/oral mucosa into lip and buccal. In future we may split into masticatory/keratinized (gingiva + hard palate) vs lining/non-keratinized (lips, cheeks, floor of mouth, soft palate). FMA distinguishes between mucosa of mouth and region of mouth (the latter including the buccal mucosa)

the mucous membrane epithelium of the mouth. It can be divided into three categories: masticatory, lining, and specialized[Wikipedia:Oral_mucosa].

uberon

buccal mucosa, mucosal lining of mouth, oral mucosa, tunica mucosa oris

UBERON:0003729

• anterior buccal gland

• gingiva

• oral epithelium