Learning Objective: By the end of this lesson, the learner will be able to describe the anatomy, vasculature, innervation, and clinical relevance of the sublingual glands and apply this knowledge to clinical and applied questions.
The sublingual glands are the smallest and most deeply situated of the three paired major salivary glands. Although they provide only 3–5% of total salivary volume, their mucous-dominant secretions are essential for lubrication, moistening of the oral mucosa, and early digestion.
Anatomical Position
The sublingual glands are almond-shaped, located on the floor of the mouth, beneath the tongue, and lie:
- Laterally: Against the mandible (forming the sublingual fossa)
- Medially: Against the genioglossus muscle
- Superiorly: Covered by mucosa forming the sublingual fold
- Anteriorly, both glands unite in a horseshoe-shaped configuration around the lingual frenulum.
The submandibular duct and lingual nerve run along the medial side of the gland.
Ducts
- Minor sublingual ducts (Rivinus): 8–20 ducts opening on the sublingual fold.
- Major sublingual duct (Bartholin, variable): may join the submandibular duct and drain via the sublingual papilla.
Vasculature
Arterial Supply
- Sublingual artery (branch of the lingual artery)
- Submental artery (branch of the facial artery)
Venous Drainage
- Sublingual veins → lingual vein
- Submental veins → facial vein
All ultimately drain to the internal jugular vein.
Activity
Innervation
Innervation is identical to that of the submandibular gland.
Parasympathetic (↑ watery saliva)
- Origin: Superior salivatory nucleus
- Pathway: Chorda tympani (CN VII) → joins lingual nerve (V3) → submandibular ganglion
- Postganglionic fibres: directly stimulate secretion + cause vasodilation
Sympathetic (↓ volume, ↑ mucous content)
- Origin: Superior cervical ganglion
- Travel on plexuses of the carotid and facial arteries into the gland
- Cause vasoconstriction → reduces saliva volume
Activity
Clinical Relevance
Ranula
A ranula is a mucous cyst in the floor of the mouth, most commonly arising from rupture of sublingual ducts due to their mucin-rich secretions. Features include:
- Smooth, blue, fluctuant swelling
- May be asymptomatic
- Large lesions can impair speech & swallowing
- If mucin tracks below the mylohyoid → cervical ranula
- Treatment may require sublingual gland excision
