The smallest of the three major salivary glands. It lies in the floor of the mouth lateral and inferior to the tongue, above the mylohyoid muscle and just medial to the sublingual fovea of the mandible. On its medial surface it is in contact with both the lingual nerve and the submandibular duct, and the geniohyoid and hyoglossus muscles. It has a number (5-15) of minor sublingual ducts which open into the floor of the mouth into the sublingual fold lateral to the lingual frenulum. There is often a major sublingual duct that opens with the submandibular duct in the sublingual caruncle. It is innervated by postganglionic parasympathetic fibers from nerve cells in the submandibular ganglion.