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M01.02.041 The Sublingual Gland
The sublingual glands are the smallest and most deeply situated of the three paired salivary glands. Although they contribute only 3-5% of total salivary volume, their predominantly mucous secretions are crucial for food lubrication, oral mucosa moisture, and initial digestion.
Overview
- Primary Function: Lubrication, moistening oral mucosa, and aiding digestion.
- Secretion Type: Mixed, primarily mucous.
Anatomical Features
Anatomical Position
- Shape: Almond-shaped.
- Location: Floor of the oral cavity beneath the tongue.
- Boundaries:
- Lateral: Mandible.
- Medial: Genioglossus muscle.
- Relationship: Submandibular duct and lingual nerve run medially.
- Boundaries:
- Special Configuration:
- Unite anteriorly in a horseshoe shape around the lingual frenulum.
- Sublingual Fold: Elevated mucosal crest extending towards the midline.
| Feature | Description |
|---|---|
| Shape | Almond-shaped |
| Adjacent Structures | Mandible, genioglossus muscle, submandibular duct, nerve |
| Special Structure | Horseshoe-shaped gland with sublingual folds |
Ductal System
- Minor Sublingual Ducts (of Rivinus):
- 8-20 ducts per gland open onto the sublingual folds.
- Major Sublingual Duct (of Bartholin):
- It may be present, joining the submandibular duct and exiting via the sublingual papillae.
Vasculature
| Feature | Supply/Drainage |
|---|---|
| Arterial Supply | Sublingual and submental arteries (branches of lingual and facial arteries). |
| Venous Drainage | Sublingual and submental veins (drain into lingual and facial veins, ultimately to the internal jugular vein). |
Innervation
Parasympathetic Innervation
- Origin: Superior salivatory nucleus.
- Pathway: Chorda tympani (facial nerve, CNVII) → Lingual nerve (mandibular branch, CNViii) → Submandibular ganglion.
- Effects:
- Secretomotor: Induces secretion.
- Vasodilator: Enhances blood supply.
Sympathetic Innervation
- Origin: Superior cervical ganglion.
- Pathway: Plexus around carotid and facial arteries → Sublingual and submental arteries.
- Effects:
- Vasoconstriction: Reduces blood flow and saliva volume.
- Saliva Composition: More mucus-rich.
| Innervation Type | Origin | Effect |
|---|---|---|
| Parasympathetic | Superior salivatory nucleus | Increases secretion and blood flow. |
| Sympathetic | Superior cervical ganglion | Reduces secretion via vasoconstriction. |
Clinical Relevance
Ranula
- Definition: A mucous cyst beneath the tongue.
- Cause: Rupture of delicate sublingual ducts with mucin accumulation.
- Types:
- Oral Ranula: Small, asymptomatic, or symptomatic causing dysphagia.
- Cervical Ranula: Swelling in the neck due to mucin collection beneath the mylohyoid muscle.
| Type | Features |
|---|---|
| Oral Ranula | Painless or causing dysphagia; may require gland excision. |
| Cervical Ranula | Presents as neck swelling; rare progression to parapharyngeal space. |
Points to Remember
- Sublingual glands are the smallest paired salivary glands, contributing 3-5% of salivary volume.
- Mixed mucous secretions help lubricate food and maintain oral moisture.
- Blood supply and venous drainage are linked to the lingual and facial vessels.
- Parasympathetic and sympathetic innervation regulate secretion and salivary flow.
- Ranulas are common disorders related to the sublingual glands due to their mucin-rich secretions.