Anatomy of Submandibular and Sublingual Glands

🦷 Submandibular & Sublingual Glands - Anatomy, Relations & Clinical Points

Submandibular gland and sublingual gland are two of the three paired major salivary glands (parotid, submandibular, sublingual).

• Submandibular = 2nd largest, walnut-shaped. Weight ~ 7–14 g.

• Sublingual = smallest, almond-shaped. Weight ~ 3–4 g.

What type of gland are submandibular and sublingual glands? What type of acini is found in each?

🗺️ Anatomy of Submandibular Gland

📍 Location of Submandibular Gland

• Located in the submandibular triangle.

• Gland has superficial and deep parts which are continuous around the posterior border of mylohyoid.

What are the boundaries of submandibular triangle?

🧱 Parts & Capsule of Submandibular Gland

• Superficial part (most visible externally) — partly enclosed by a capsule derived from the investing layer of deep cervical fascia (splits into superficial and deep lamina at greater cornu of hyoid).

• Deep part lies deep to mylohyoid, extends forward between mylohyoid and hyoglossus up to posterior sublingual gland.

What are the attachments of submandibular gland capsule?

🔍 Parts and Relations of Submandibular Gland

1- Superficial Part of Submandibular Gland

• Anterior end: reaches anterior belly of digastric.
• Posterior end: up to stylomandibular ligament (separates it from parotid). Groove for ascending limb of facial artery’s cervical loop.

Three surfaces (Superficial part)

1. Inferior (superficial) surface — from superficial → deep: skin → superficial fascia (platysma + cervical branch of facial nerve) → deep fascia → facial vein → submandibular lymph nodes.

2. Lateral surface — related to submandibular fossa of mandible, medial pterygoid near insertion, facial artery (loops between bone and gland then winds around mandible).

3. Medial surface — extensive; subdivided:

   • Anterior medial: mylohyoid, submental branch of facial artery, mylohyoid nerve/vessels.
   • Middle medial: hyoglossus, styloglossus, lingual nerve, hypoglossal nerve, submandibular ganglion.
   • Posterior medial: styloglossus, stylopharyngeus, glossopharyngeal nerve, posterior belly digastric, superior pharyngeal constrictor (lateral pharyngeal wall), lingual & hypoglossal relations, 1st part of lingual artery.

2- Deep part relations

• Lateral: mylohyoid.
• Medial: hyoglossus.
• Superior: lingual nerve and submandibular ganglion.
• Inferior: hypoglossal nerve with veins.

How do you bimanually palpate the submandibular gland and why?

How to differentiate between a swelling of submandibular gland vs swelling of submandibular lymph node?

🧭 Submandibular (Wharton’s) Duct

• Length: ~5 cm.

• Origin: from middle of deep surface of superficial part; appears at anterior end of deep part.

• Course: runs forward on hyoglossus between lingual nerve and hypoglossal nerve (lingual nerve loops under the duct), then continues between sublingual gland & genioglossus → opens at sublingual papilla on each side of frenulum linguae.

Describe the relation of the lingual nerve to the submandibular duct.

🩸 Blood Supply & Lymphatic Supply of Submandibular Gland

• Arterial: Sublingual & submental arteries (branches of facial / lingual systems).

• Venous: Correspond to arteries → drain into internal jugular.

• Lymphatics: Submandibular nodes → jugulodigastric deep cervical nodes.

🧠 Nerve Supply of Submandibular Gland

• Parasympathetic (secretomotor — watery)
• Sympathetic (viscous secretion + vasomotor): Postganglionic fibres from superior cervical ganglion via plexus on facial artery.
• Sensory: Lingual nerve.

What is the pathway of parasympathetic innervation of Submandibular gland?

🪴 Anatomy of Sublingual Gland

📍 Location & Appearance of Sublingual Gland

• Lies in the floor of mouth, between mucous membrane and mylohyoid, in the sublingual fossa of mandible (above anterior mylohyoid line).

• Almond-shaped, mucous acini, ~3–4 g.

🔁 Relations of Sublingual Gland

• Anterior: meets opposite sublingual gland near midline (symphysis menti).
• Posterior: deep part of submandibular gland.
• Superior: oral mucosa forming sublingual fold.
• Inferior: mylohyoid muscle.
• Lateral: sublingual fossa of mandible.
• Medial: genioglossus (separated by submandibular duct & lingual nerve).

🧩 Sublingual Ducts

• Multiple small ducts (8–20) — ducts of Rivinus open individually into floor of mouth on sublingual fold.

• Anterior group of ducts may unite to form Bartholin’s (sublingual) duct, which typically opens into the submandibular (Wharton’s) duct.

🩸Blood Supply, Lymphatic Drainage & Nerve Supply of Sublingual Gland

• Arterial: Sublingual & submental arteries.

• Venous: Veins to internal jugular.

• Lymph: Submental & submandibular nodes.

• Nerve supply: Same pattern as submandibular

How does parasympathetic innervation to sublingual differ from submandibular?

What is Ranula?

📝 Summary table (very high-yield)