20. Tongue. Embryonic development. Macroscopic, microscopic, ultramicroscopic and functional characteristics. Lingual papillae – types. Muscles of the tongue. Blood and nerve supply.

TONGUE

• The tongue is a muscular organ covered by mucous membrane. It is concerned with taste, deglutition, and speech.
• It has apex, root, body, and 2 surfaces (dorsal and ventral).
• Apex: is directed anteriorly touching the lower incisor teeth.
• Root: is attached to mandible and hyoid bone.
• Ventral (inferior) surface: is smooth.
• Dorsal surface: is rough.

Surfaces of the tongue:

Ventral Surface:

• It shows the following:
• Frenulum lingue: formed by the mucosa in the median plane between the tongue and floor of the mouth.
• Deep lingual vein: on either sides of the frenulum.
• Fimbriated fold: plica fimbriata lateral to the deep lingual vein.

Dorsal Surfaces:

• It is divided by V-shaped sulcus terminalis into anterior 2/3 and posterior 1/3.
• The apex of the sulcus: is directed posteriorly. It is marked by foramen caecum (?).
• Anterior 2/3 are called: oral part of the tongue.
• Posterior 1/3 is called: pharyngeal part of the tongue.
• √ Anterior 2/3 :
• Called the oral part (anterior to palatoglossal arches).
• Develops from 1st pharyngeal arch.
• Thick & rough (has papillae)
• √ Posterior 1/3
• Called pharyngeal part.
• Develops from 4th pharyngeal arches.
• Thin & smooth