Submandibular salivary gland

SUBMANDIBULAR SALIVARY GLAND

Submandibular Gland Superficial Part Relations Deep Part Blood & Lymph Nerve Supply Submandibular Duct

1 Submandibular Salivary Gland

  • It is a large salivary gland, situated in the anterior part of the digastric triangle.

Dimensions and Shape

  • About the size of a walnut.
  • Weight: 15–20 g.
  • It is roughly J-shaped.
  • It is indented by the posterior border of the mylohyoid, which divides it into:
    1. Larger superficial part → lies superficial to the muscle.
    2. Small deep part → lies deep to the muscle.

2 Superficial Part

  • This part of the gland fills the digastric triangle.
  • It extends superiorly, deep to the mandible, up to the mylohyoid line.
  • Inferiorly, it overlaps:
    • Stylohyoid
    • Posterior belly of digastric
  • It has three surfaces:
    • Inferior
    • Lateral
    • Medial.

Coverings of Superficial Part

It is partially enclosed between two layers of deep cervical fascia.

Superficial Layer of Fascia

  • Covers the inferior surface of the gland.
  • Is attached to the base of the mandible.

Deep Layer of Fascia

  • Covers the medial surface of the gland.
  • Lies superior to the mylohyoid line of the mandible.

3 Relations of Superficial Part

A. Inferior or Superficial Surface

It is covered by:

  1. Skin
  2. Platysma
  3. Cervical branch of facial nerve
  4. Investing fascia
  5. Facial vein
  6. Submandibular lymph nodes.

B. Lateral Surface

It is related to:

  1. Submandibular fossa on the mandible
  2. Insertion of medial pterygoid
  3. Facial artery.

C. Medial Surface

It is divided into three parts:

1. Anterior Part

Related to:

  • Mylohyoid
  • Submental branch of facial artery
  • Mylohyoid nerve and vessels

2. Middle Part

Related to:

  • Hyoglossus
  • Styloglossus
  • Lingual artery
  • XII nerve

3. Posterior Part

Related to:

  • Stylohyoid
  • Styloglossus
  • IX nerve.

4 Deep Part

  • This part is small in size.
  • It lies:
    • Deep to the mylohyoid
    • Superficial to the hyoglossus and styloglossus
  • Posteriorly, it is continuous with the superficial part around the posterior border of the mylohyoid.
  • Anteriorly, it extends up to the posterior end of the sublingual gland.

Relations of Deep Part

It is present between the mylohyoid and hyoglossus.

Laterally

  • Mylohyoid (removed)

Medially

  • Hyoglossus

Above

  • Lingual nerve with submandibular ganglion

Below

  • Hypoglossal nerve.

5 Blood Supply and Lymphatic Drainage

Blood Supply

  • The submandibular gland is supplied by the facial artery.
  • The veins drain into the:
    • Common facial vein, or
    • Lingual vein.

Lymphatic Drainage

  • Lymph passes to the submandibular lymph nodes.

6 Nerve Supply

  • It is supplied by branches from the submandibular ganglion.
  • These branches convey:
  1. Secretomotor fibres
  2. Sensory fibres from the lingual nerve
  3. Vasomotor sympathetic fibres from the plexus on the facial artery.

7 Submandibular Duct / Wharton’s Duct

  • It is thin-walled.
  • It is about 5 cm long.
  • It is named after Thomas Wharton, English anatomist, 1614–73.
  • He also discovered Wharton’s jelly of the umbilical cord.

Course

  • It emerges at the anterior end of the deep part of the gland.
  • It runs upwards and forwards on the hyoglossus.
  • It runs between:
    • Lingual nerve
    • Hypoglossal nerve
  • At the anterior border of the hyoglossus, the duct is crossed by the lingual nerve.

Opening

  • It opens on the floor of the mouth.
  • It opens on the summit of the sublingual papilla.
  • The opening is at the side of the frenulum of the tongue.