25.1 Organisation of the pharynx

 
The  tongue  


Position:

  • Floor of the mouth

Parts:
Roof:

  • Portion attached to floor of the mouth

Body:

  • Part in the oral cavity

Tip:

  • Apex pointing anteriorly

 
 
 
 

Surfaces & Features


Dorsum

  • Divided by V-shaped sulcus terminalis into anterior pre-sulcal part and posterior post-sulcal part.
  • Apex of the V points backwards. Foramen caecum is at the apex

Roughened by:

  • Circumvallate papillae infront of sulcus terminalis

  • Foliate papillae on each side of the tongue

  • Conical papillae parallel and posterior to sulcus terminalis

  • Fungiform papillae over tip and sides

  • Filiform papillae, covering presulcal part

  • Post sulcal part has elevations consisting lingual tonsils

Ventral/ inferior surface

Shows the following features

  • Frenulum linguae- median mucosal fold connecting the tongue to the floor

  • Deep lingual vein on each side parallel to the midline

  • Plica fimbriata lateral to the  vein turning towards the apex

 

Muscles of the tongue


Intrinsic muscle- alter the shape of the tongue:

  • Inferior and superior longitudinal
  • Transverse
  • Vertical

 

 
Extrinsic muscles of tongue

Muscle

Origin

Insertion

Action

Genioglossus

Superior genoid tubercle of mandible
  • Substance of corresponding half of tongue
  • Hyoid bone
  • Lower fibres protrude
  • Tongue depression

Hypoglossus

Greater horn and body of hyoid
  • Posterior half of side of tongue
  • Interdigitate with styloglossus

Draws side of tongue downwards

Styloglossus

Styloid process
Stylohyoid ligament

Whole length if side of tongue
Intedigitates with hyoglossus

Draws side of tongue upwards and backwards

Palatoglossus

Lower surface of palatine aponeurosis

Posterior part of the side of the tongue

Bilaterally pull tongue upwards to constrict fauceal isthmus

 

Blood supply

Arterial

  • Deep lingual artery- body and tip
  • Dorsal lingual- pharyngeal part and dorsum
  • Unilateral supply
  • Little anastomosis across midline

Venous

  • Dorsal lingual veins
  • Deep lingual veins
  • These join to form lingual vein- common facial vein or internal jugular vein

Innervation

Taste

  • Anterior 2/3- Facial nerve (Chorda tympani, CN VII).
  • posterior 1/3- Glossopharyngeal nerve (CN IX)

General sensation

  • Anterior 2/3- Lingual nerve which is a branch of V3 of the Trigeminal nerve CN V.
  • Posterior 1/3 -Glossopharyngeal nerve (CN IX).

Muscles

  • All intrinsic and extrinsic muscles of the tongue are supplied by the Hypoglossal nerve (CN XII),
  • Except for one of the extinsic muscles, palatoglossus, which is inervated by pharyngeal plexus.

 

Lymphatic drainage

Part
Nodes

Tip and ventral surface
  • Sub mental
  • Sub mandibular
  • Jugulo digastric
Side of presulcal part
  • Submandibular
  • Jugulo-omohyoid
  • Jugulo-digastric
Post sulcal part (Bilateral drainage)
  • Jugulo-digastric
  • Sub mandibular
  • Retropharyngeal

 

The Oral cavity and Pharynx