Human mandibular prenatal growth: bivariate and multivariate growth allometry comparing different mandibular...

Area of Science:

• Human Embryology
• Craniofacial Development
• Biometry

Background:

• Understanding human fetal mandibular growth is crucial for diagnosing and treating craniofacial anomalies.
• Prenatal development involves complex, coordinated growth patterns of skeletal structures.

Purpose of the Study:

• To analyze mandibular growth patterns in human fetuses using bivariate and multivariate statistical methods.
• To identify specific dimensions of the mandible that exhibit positive or negative allometric growth during gestation.

Main Methods:

• Bivariate allometry and Principal Component Analysis (PCA) were applied to measurements from 36 human fetuses (13-37 weeks gestation).
• Key mandibular dimensions were measured and correlated with fetal weight.
• Growth rates and allometric relationships for various mandibular landmarks were assessed.

Main Results:

• No mandibular dimension exhibited isometric growth; all showed allometric patterns.
• Negative allometry was observed for distances like caput mandibulae-gnathion and gonion-processus coronoideus.
• Positive allometry was noted for gonion-gnathion (left side) and symphyseal height (both sides).
• The mandibular body demonstrated greater growth in length and height compared to the ramus during the second and third trimesters.
• Symphyseal height showed the highest growth rate, while the angulus mandibulae had a negative correlation with other linear dimensions.

Conclusions:

• Fetal mandibular growth is characterized by significant allometry, with differential growth rates between the body and ramus.
• Symphyseal height is a key indicator of rapid mandibular growth during late gestation.
• These findings provide insights into normal craniofacial development and potential deviations.