Minor trauma to the floor of the mouth is thought to damage the delicate ducts that drain saliva from the sublingual gland into the oral cavity. The lesion is a mucous extravasation cyst (mucocele) of the floor of mouth, although a<unk>  is often larger than other mucoceles (mainly because the overlying mucosa is thicker). They can grow so large that they fill the mouth. The most usual source of the mucin spillage is the sublingual salivary gland, but<unk> e may also arise from the submandibular duct or the minor salivary glands in the floor of the mouth. A cervical<unk>  occurs when the spilled mucin dissects its way through the mylohyoid muscle, which separates the sublingual space from the submandibular space, and creates a swelling in the neck. It may occur following rupture of a simple<unk> . Rarely,<unk> e may extend backwards into the parapharyngeal space.
Ranula
Microgyrus
Ateronon
Syrinx 
Stenopaeic slit
Pinguecula
Otic pit
Orbital septum