Mandible and Tongue Development

Abstract

The tongue and mandible have common origins. They arise simultaneously from the mandibular arch and are coordinated in their development and growth, which is evident from several clinical conditions such as Pierre Robin sequence. Here, we review in detail the molecular networks controlling both mandible and tongue development. We also discuss their mechanical relationship and evolution as well as the potential for stem cell-based therapies for disorders affecting these organs.

Keywords: Mandible; Mandibular osteogenesis; Meckel's cartilage; Pierre Robin sequence; Tongue; Tongue myogenesis.

Figure 1

Scheme of mandible development. (A) The first BA subdivides into maxillary and mandibular prominences at E10.5. At this stage, both prominences are solely constituted by CNCC-derived mesenchyme, which is covered by epithelium. (B) At E12.5, the MC develops in the mandibular primordium and mesenchymal cells condense close to it. (C) Mesenchymal cells start differentiating into osteoblasts. An osteogenic front composed of undifferentiated cells surrounds the differentiated osteoblasts. (D) Differentiation progresses in the mandibular primordium at E14.5. (E) The MC gives rise to the symphysis in the distal region and to the malleus and incus in the proximal region of the mandible. Abbreviations: E, eye; MC, Meckel's cartilage; I, incus; M, malleus; PS, palatal shelf; S, symphysis; T, tongue.

Figure 2

Mechanical relationship between the mandible and tongue. (A) and (B) show schemes of a sagittal view of the skull of control and a PRS mouse model at newborn stage, respectively. (C) and (D) are schemes of corresponding coronal sections.