Development of tongue

DEVELOPMENT

Appears – 4th week.

It involves

DEVELOPMENT OF MUCOUS MEMBRANE

MUSCLES OF TONGUE

FIBROMUSCULAR STROMA

DEVELOPMENT OF THE TONGUE MUSCLES

Occipital myotomes – formed by the fusion of four

pre –cervical somites

Supplied by hypoglossal nerve (nerve of occipital myotome)

FIBROMUSCULAR STROMA

Developed in situ from the mesoderm of the adjacent arches

Floor of primitive pharynx

DEVELOPMENT OF MUCOUS MEMBRANE

LINGUAL SWELLINGS

TUBERCULUM IMPAR

HYPOBRANCHIAL EMINENCE

• Anterior 2/3rd /body - Lateral lingual swellings+ tuberculum impar.

• Posterior part 1/3rd /root – cranial part of copula.

• Sulcus terminalis separate anterior from posterior.

• Posterior most part - 4th arch.

• Muscle - occipital myotomes.

NERVE SUPPLY

• Motor - hypoglossal nerve (XII)

• Sensory

• ANTERIOR 2/3rd

– general sensory – lingual branch of mandibular division of trigeminal nerve(1st arch).

– Special sensory – chorda tympanic branch of facial nerve.

– Circumvallate papillae – glossopharyngeal nerve(3rd arch)

• POSTERIOR 1/3rd

– General sensory & special sensory - glossopharyngeal nerve.

• Posterior most portion close to the epiglottis – superior laryngeal branch of

vagus nerve.

Ankyloglossia

Shortening of frenulum linguae

Produce difficulty in speech

Corrected by operation -

frenulectomy

Bifid tongue

MICROGLOSSIA

MACROGLOSSIA

LINGUAL THYRIOD

APPLIED ANATOMY

• Injury to hypoglossal nerve

• Grand mal epilepsy

• Glossitis

• Importance of the tongue

*Red – glossitis

*Red beef tongue –metabolic disorders

*fissured tongue – vitamin deficiency

*Blue tongue – cyanosis

*Yellow -jaundice

*Black hairy tongue –aids

*Coated – fever and other

*pathological condition

Sublingual absorption of drugs - (aspirin)