DEVELOPMENT OF TONGUE – MESOBRANCHIAL REGION

What is the mesobranchial region?

Triangular area in the floor of the pharynx. Source of tongue, thyroid, and epiglottis development

What does the anterior 2/3 of the tongue develop from?

From 2 lateral lingual swellings and tuberculum impar (1st arch). Lateral swellings overgrow the tuberculum impar

What is the nerve supply to the anterior 2/3 of the tongue?

Sensation: Mandibular nerve (V3). Taste: Chorda tympani (VII)

What forms the posterior 1/3 of the tongue?

Hypobranchial eminence (ventral part). Derived from 3rd and part of 4th arch mesoderm

What is the nerve supply to the posterior 1/3 of the tongue?

Glossopharyngeal nerve (IX)

What forms the epiglottis and valleculae?

Dorsal part of the hypobranchial eminence (from 4th arch). Nerve: Superior laryngeal nerve (branch of X)

What is the sulcus terminalis and foramen cecum?

Sulcus terminalis: V-shaped groove separating anterior 2/3 and posterior 1/3.

Foramen cecum: Origin site of thyroid primordium