Developmental malformations of human tongue and associated syndromes (review).

The development of the tongue begins as known, in the floor of the primitive oral cavity, when the human embryo is four weeks old. More specifically, the tongue develops from the region of the first three or four branchial arches during the period that the external face develops. Malformations of the tongue, are structural defects, present at birth and happening during embryogenesis. The most common malformations are: 1. Aglossia 2. Microglossia, which is always combined with other defects and syndromes, like Moëbius syndrome 3. Macroglossia, which is commonly associated with cretinism, Down's syndrome, Hunter's syndrome, Sanfilippo syndrome and other types of mental retardation 4. Accessory tongue 5. Long tongue 6. Cleft or Bifid tongue, condition very usual in patients with the orodigitofacial syndrome 7. Glossitis Rhombica Mediana, a developmental malformation? 8. Lingual thyroid. Malformations are extensively analysed and discussed.