INTRODUCTION:

It is a muscular organ situated in the floor of the mouth. It is associated with the following functions as -
  • Taste.
  • Speech.
  • Chewing.
  • Deglutition.

FEATURES:

The tongue has - a root, a tip, and a body.

1. ROOT:

It is attached to the styloid process and soft palate above and to the mandible and the hyoid bone below. It is also related to the geniohyoid and mylohyoid muscles.

2. TIP Of TONGUE:

The tip of the tongue forms the anterior free end which at rest lies behind the upper incisor teeth.

3. BODY Of TONGUE:

It is divided into-
  • A curved surface or dorsum.
  • An Inferior surface.

Dorsum Of Tongue:

It is convex in all directions. It is divided by a v-shaped groove, the Sulcus terminalis into-
  • An oral part / anterior two- thirds.
  • A pharyngeal part.
  • Small Posterior most part.

The two limbs of V groove meet at a median pit known as the Foramen Caecum.

A. Oral or Papillary part of the Tongue:

  • It is placed on the floor of the month. 
  • Its margins are free and in contact with the gums and teeth.
  • The superior surface of the oral parts shows a median furrow and is covered with papillae which make it rough.
  • The Inferior surface is covered with a smooth mucosa membrane, which shows a median fold called the frenulum linguae.
  • On either side of the frenulum, there is a prominence produced by the deep lingual veins.
  • More laterally there is a fold called PLICA FIMBRIATA.

B. Pharyngeal or Lymphoid Part :

  • It lies behind the palatoglossal arch and the Sulcus terminalis.
  • It forms the anterior wall of the oropharynx.
  • The mucosa has no papillae but has many Lymphoid follicles which constitute lingual tonsils.

C. Posterior most part of the Tongue:

It is connected to the epiglottis by three folds of mucosa membrane.

PAPILLAE OF THE TONGUE:

  • These are projections of mucous membrane or cerium which gives the characteristics roughness to the anterior ⅔ rd surface. 
  • These are of three types as follows:

1. Vallate or circumvallate papillae:

  • These are large in size (1-2 mm in size diameter).
  • They lie just a front of the Sulcus terminalis.
  • Each papilla is a cylindrical projection surrounded by the circular Sulcus.
  • The wall of the papillae have taste buds.

2. Fungiform papillae:

  • It lies near the tip, margins of the tongue and some are scattered over the surface.
  • They are smaller than vallate papillae.
  • Each papilla consists of the narrow pedicle and a large rounded head and have a bright red color.

3. Filiform Papillae:- (or conical papillae) :

  • They are smallest but numerous of the lingual papillae.
  • It covers the presulcus area of the dorsum of the tongue and give it a characteristic velvety appearance.

ARTERIAL SUPPLY:

Tongue is mainly supplied by the LINGUAL ARTERY, a branch of the external carotid artery and additional supply from ascending pharyngeal artery and tonsillar artery.

VENOUS DRAINAGE:

The deep lingual vein is the largest and principal vein of the tongue which ends in the internal jugular vein.

NERVE SUPPLY:

Motor Nerve:

  • All the intrinsic and extrinsic muscles except palatoglossus are supplied by the Hypoglossal Nerve.
  • The palatoglossus is supplied by the cranial root of the accessory nerve.

Sensory Nerve:

  • The lingual nerve for general sensation and chorda tympani is the nerve for taste for the anterior ⅔ .
  • Posterior ⅓ rd is supplied by the glossopharyngeal nerve for both general and taste sensation.
  • The Posterior most part is supplied by the internal laryngeal branch.

LYMPHATIC DRAINAGE:

  • Tip Of Tongue - Submental Nodes.
  • Anterior ⅔ rd part - Submandibular nodes.
  • Posterior ⅓ rd part - upper deep cervical lymph nodes.
  • The whole lymph finally drains into the JUGLO - OMOHYOID Nodes.

APPLIED ANATOMY:

  1. Glossitis:- Inflammation of tongue or a part of generalized ulceration of oral cavity or stomatitis.
  2. Paralysis of tongue due to injury into Hypoglossal Nerve, result in loss of motor function of the tongue.
  3. Carcinoma of Tongue is quite common, better treated by radiotherapy.
  4. Sorbilrate is taken sublingually for immediate relief from angina pectoris.
  5. Genioglossus is called the “ safety muscle of the tongue” because it is paralyzed, the tongue will fall back on the oropharynx and block the air passage.