5. Anterior 2/3
The anterior two thirds of the tongue is formed by fusion of the
tuberculum impar and the two lingual swellings.
supplied by the lingual branch of the mandibular nerve
Posterior 1/3
The posterior one-third of the tongue is formed from the cranial part of the
hypobranchial eminence (copula)
supplied by the glossopharyngeal nerve,
6. The posterior most part of the tongue is derived from the fourth arch
supplied by the superior laryngeal nerve
7. The musculature of the tongue is
derived from the occipital
myotomes
8. The mucosa of tongue is derived from endoderm of foregut
The fibroareolar stroma is derived from the neural crest
The circumvallate papillae of tongue develop from the cranial part
of hypobranchial eminence and migrate to the anterior aspect of
sulcus terminalis. They are supplied by glossopharyngeal nerve
9. Development of sensory nerves
Lingual nerve
Chorda tympani nerve
Glossopharyngeal nerve
14. Papillae of the tongue
Projections of mucous membrane which
gives the anterior 2/3rd of tongue its
characteristic roughness
15. Circumvallete papillae
Largest among papillae
Shape: dome shaped
Size: 1-2mm in diameter
Number: 8 to 12
Location: in front of sulcus terminalis
Arranged in V shaped
16. Filiform papillae
Hair like or thread like in appearance
Function: facilitate mastication
No taste buds
Histologically
cone shaped appearance
lined by stratified squamous epithelium.
20. Taste buds
The receptors for taste
Located on the surface of the tongue, soft
palate and epiglottis.
Each taste bud contains approximately 50–
100 cells and has a life span of 10–14 days
21.
22. Pharyngeal 1/3 of the tongue
Lies behind sulcus terminalis
Forms anterior wall of oropharynx
No papillae
Consist of lingual tonsil
25. Ankyloglossia
Congenital anamoly characterized by abnormal short lingual frenulum
Resists mobility of tongue
Clinical features
Tongue has heart shaped protrusion
Protrusion is limited
32. genioglossus
Origin
from the superior genial tubercle
Insertion:
hyoid body near the midline.
posterior part of the tongue
ventral surface of the tongue
33. Action
Protrusion
Bilaterally: Central part depression
Unilaterally: Diverges to opposite side
Clinical importance
If paralysed, the tongue falls posteriorly
Total relaxation occurs during general anaesthesia
34. HYOGLOSSUS
Origin
greater cornu and from the front of the
body of the hyoid bone
Insertion
Lateral border of the tongue
Nerve: hypoglossal nerve
Action: Depression
35. STYLOGLOSSUS
Origin
Tip and anterior surface of styloid process
Insertion
Lateral border of the tongue
Nerve supply
hypoglossal nerve
Action
pull the tongue upwards and backwards
36. Palatoglossus
Origin: inferior surface of palatine aponeurosis
Insertion: lateral margins of tongue
Action: elevates the posterior part of the tongue
42. Lingual artery
Branch of external carotid artery
Near the tip of the tongue, the lingual artery anastomoses with its fellow from the
opposite side.
Branches
dorsal lingual artery
sublingual artery
deep lingual artery
43. Dorsal lingual artery
Supply
mucous membrane of the
dorsum of the tongue,
the palatoglossal arch,
soft palate,
tonsil
epiglottis.
45. deep lingual artery
Supplies anterior part of the tongue
46. Clinical importance
Injury to the lingual artery during surgery can lead to life-threatening hemorrhage
If both lingual arteries are damaged, leads to necrosis of the tongue
lingual artery stenosis is seen in patients with radiotherapy
47. Venous drainage
deep lingual vein: drains the tip of the tongue
Dorsal lingual veins: drain the dorsum and sides of the tongue and join the lingual
veins accompanying the lingual artery.
49. Lymphatic drainage
Tip- drain to submental nodes
Anterior 2/3rd – submandibular
Posterior part – deep cervical nodes
The deep cervical nodes involve jugulo
omohyoid and jugulo digastric nodes
50.
51. Clinical importance
Presence of rich network of lymphatics is responsible for swelling of tongue in
acute glossitis
CA of posterior 1/3rd of the tongue is more dangerous due to bilateral lymphatic
spread
53. Motor
All muscles of the tongue are innervated by the hypoglossal
nerve [XII] except for the palatoglossus muscle, which is
innervated by the vagus nerve [X].
54. Sensory
Anterior two-thirds (oral)
General sensation: mandibular nerve [V3] via lingual nerve
Special sensation (taste): facial nerve [VII] via chorda tympani
Posterior one-third (pharyngeal)
General and special (taste) sensation via glossopharyngeal nerve
[IX
55. Posterior one-third (pharyngeal)
General and special (taste) sensation via glossopharyngeal nerve [IX]
Posterior most part
Innervated by vagus nerve through internal laryngeal nerve
56. Clinical importance
Injury to hypoglossal nerve
Trauma like fractures mandible
Paralysis of one side of tongue
Tongue deviates to paralysed side during protrusion
Injury to both sides causes tongue to be motionless
57. Functions of tongue
Mastication
Tongue is a important accessory organ in digestive system
Crushes food against hard palate, during mastication and manipulation of food for
softening prior to swallowing
During mastication food is converted into bolus and is placed on tongue and
travelled posteriorly along the tongue, passes the food over epiglottis into the
oesophagus
58. Speech
Tongue is the principle articulator
Intrinsic muscles of tongue enable shaping of tongue which facilitates speech
Voice is produced by larynx and modified by tongue by constantly altering its
shape, position by contracting lips, teeth, alveolar process, hard palate and soft
palate
