Development of the facial midline

Area of Science:

• Developmental biology
• Craniofacial anatomy
• Embryology

Background:

• Traditional embryology struggles to explain the 3D development of the facial midline.
• A new model proposes paired A fields originating from the prechordal mesendoderm for facial midline development.

Purpose of the Study:

• To present evidence supporting the field theory model for facial development.
• To explain the internal structure of the nose and oronasal midline.

Main Methods:

• Analysis of fetal specimens with isolated internal carotid artery (ICA) systems.
• Examination of neuromeric CNS development models.
• Study of Dlx5 gene mutants.
• Investigation of clinical models of facial and neurological disorders.

Main Results:

• A distinct vascular watershed in the embryonic nasal capsule supports the A field model.
• Field theory explains nasal capsule contents and provides a genetic basis via the neuromeric model.
• Dlx5 gene mutants show A field deletion patterns, linking nasal placodes to A fields.
• Clinical disorders like holoprosencephaly and Kallmann syndrome illustrate A field developmental disturbances.

Conclusions:

• The paired A field model offers a comprehensive explanation for facial midline development.
• This model integrates embryology, genetics, and vascular supply.
• Understanding A field development is crucial for comprehending craniofacial anomalies.