Ontogenetic variation in human nasal morphology.

Area of Science:

• Human Anatomy
• Evolutionary Biology
• Anthropology

Background:

• Nasal morphology is linked to respiratory functions like air heating and humidification.
• Previous research often overlooks developmental changes, focusing on adult nasal structures.

Purpose of the Study:

• To determine when adult-specific human nasal morphology emerges during development (ontogeny).
• To investigate how ancestry and sex influence nasal shape development.
• To explore the interplay of climatic and metabolic pressures on nasal form.

Main Methods:

• Utilized cross-sectional CT data from 321 individuals across African, European, and Arctic samples, from infancy to adulthood.
• Applied generalized Procrustes and form-space principal component analyses to 18 facial and nasal landmarks.
• Analyzed growth curves to track morphological changes over age.

Main Results:

• Nasal size changes (PC1) correlate with age across all groups, while nasal shape differences (PC2) distinguish ancestral groups.
• The majority of nasal size and shape is established by age five, with comparable growth trajectories across samples.
• Females show a shorter nasal growth period than males; anterior and posterior nasal regions exhibit distinct developmental patterns.

Conclusions:

• Human nasal morphology is shaped by multiple ontogenetic factors, including metabolic and climatic adaptations.
• Early developmental stages are critical for establishing adult nasal form.
• Nasal cavity development reflects a balance between respiratory efficiency and environmental conditioning.