<prompt> After a radiograph revealed a sialolith stone in a patients right submandibular duct, the surgeon exposed the duct an intraoral approach. In this approach, what tissues or structures must be cut through?Mucous membrane onlyMucous membrane and genioglossus muscleMucous membrane and mylohyoid muscleMucous membrane and hyoglossus muscle  <response>: The submandibular duct is found deep to the mucous membrane of the mouth, but superficial to the muscles of the tongue and the muscles on the floor of the mouth. So, genioglossus, mylohyoid, and hyoglossus are deep to the submandibular duct. 