Tongue

• Tongue is a muscular organ situated in floor of mouth that plays crucial role is tasting, swallowing, speaking and chewing.
• Anatomical parts of tongue:

  • Apex (tip): forms anterior free end of tongue. Lies behind upper incisor teeth at rest.
  • Root: back part of tongue that anchors it to floor of mouth. Attached to styloid process + soft palate above and mandible + hyoid bone bellow.
  • Body: central part. 2 surfaces: Upper surface (convex in all direction) subdivided into oral, pharyngeal and posteriormost parts.

  
• Oral( anterior 2/3) and pharyngeal(post 1/3) part of body of tongue are divided by a v-shaped groove known as sulcus terminalis.

  • The sulci has 2 limbs that meet at a median pit known as foramen caecum

  
• Oral part of tongue (anterior 2/3)

  Includes apex and body
• Oral part of tongue

  Terminates at sulcus terminalis
• Oral part of tongue


  Placed on floor of mouth
• Margins of oral part of tongue


  Free and in contact with teeth and gums
• Margins of oral part of tongue

  • Each has 4-5 vertical folds just in front of palatoglossal arch known as foliate papillae
• Superior surface of oral part of tongue

  Covered with vallate, filiform and fungiform papillae
• Superior surface of oral part of tongue

  Has a longitudinal midline groove running from tip to foramen cecum, marking the embryological point of fusion of the Lateral lingual swellings that form oral tongue
• Inferior surface of oral part of tongue

  Covered with smooth mucous membrane which is continuous with mucosa of floor of mouth
• Inferior surface of oral part of tongue

  Shows a median fold: frenelum linguae
• Inferior surface of oral part of tongue


  • On each side of the lingual frenelum, prominent deep lingual veins are present
• Lateral to lingual veins

  Fold of mucosa known as plica fimbriata
• Lingual frenelum

  
• Pharyngeal part of tongue

  • Present behind sulcus terminalis and palatoglossal arches
  • Forms anterior wall of oropharynx
  • the mucous membrane has no papillae
  • Mucosa is populated by aggregates of lymphatic follicles that constitute the lingual tonsils.
  • Mucous glands are also present.

  
• Posteriomost part of tongue lies in oropharynx

  • connected to epiglottis by 3 folds of mucous membrane
  • Right and left lateral glossoepiglottic folds and an median glossoepiglotic fold.
  • The lateral folds borders a depression present on either side of median fold known as vallecula

  
• tongue diagram

  
• Tongue is a muscular organ.

  • All muscle of tongue are paired, with each copy being found on either side of the median fibrous septum.
  • 2 main types of muscles:
  • Extrinsic muscles: extend outside tongue to anchor it to surrounding bony structure
  • Intrinsic muscles: confined to each half of the organ contributing to altering its shape.
• Intrinsic muscles of tongue are responsible for adjusting the shape and orientation of the organ.

  • Superior longitudinal m: shortens the tongue and elevates the tip and sides superiorly
  • Inferior longitudinal m: shortens; curls the tip of tongue inferiorly.
  • Transverse m: makes tongue narrow and increases thickness.
  • Vertical m: at borders of anterior side of tongu. Makes tongue flattened and broad.

  
• Extrinsic muscles of tongue: insert it and controls position

  • Connects tongue to mandible: genioglossus: protudes tongue
  • To hyoid bone: hyoglossus: depresses tongue
  • To styloid process: styloglossus: retracts
  • To palate: palatoglossus: elevates
• Tongue muscles

  
• Arterial supply of tongue

  • Lingual artery (brach of external carotid)
  • Root is also supplied by tonsilar (brach of facial) and ascending pharyngeal brach of external carotid
• Venous drainage of tongue

  • Deep lingual vein: chief vein of tongue seen on post surface
  • Venae comittantes: accompanies lingual artery
  • Venae committantes: accompanying hypoglossal n

  These unites at posterior border of hypoglossus to form lingual vein which drains into internal jugular vein

  
• Lymphatic drainange of tongue

  • Tip: submental nodes
  • Anterior 2/3: submandibular nodes
  • Posterior 1/3: deep cervical lymph nodes

  whole lymph then drains into jugolo-omohyoid nodes
• Nerve supply of tongue

  • Motor: Hypoglossal n: all intrinsic and extrinsic muscles except palatoglossus (cranial root of accessory n)
  • Sensory: Lingual n (general sensation) + chorda tympani (taste sensation): anterior 2/3 except circumvallate papillae.

  Glossopharyngeal n: for both taste and general sensation to post 1/3 .

  Vagus n: both taste and general sensation to posteriomost part near epiglotti.
• Muscles of tongue