Title : The shape evolution of the human thoracic cage from birth to adulthood: Characterization and acceleration
Abstract:
Background: Despite its clinical importance, the morphological development of the human thoracic cage from infancy through adulthood remains insufficiently documented. This study aims to establish a detailed, quantitative, and qualitative timeline of thoracic cage evolution in males and females using an extensive sample of chest CT scans.
Methods: CT scans of 176 typically developing individuals (116 males, 60 females), aged 0–29 years, were analyzed and categorized into six age groups. Key thoracic parameters kyphosis, height, width, and depth were measured. Additionally, Geometric Morphometric Analysis (GMA) was conducted on a subset of 63 cases.
Results: At birth, thoracic height was 45% of its adult value, with marked growth spurts during early childhood and puberty. Notable anatomical changes included significant increases in anteroposterior depth (especially at T7) and width (particularly at T3). Sagittal and frontal shape ratios also evolved, indicating elongation of the thorax. Thoracic kyphosis increased from 24° to 37°, with distinct growth phases. Principal component analysis revealed two developmental stages: rapid shape changes from birth to four years (PC1: 46.2% variance), followed by puberty-related modifications (PC2: 10.5%). Gender differences emerged post-14 years, with males displaying larger dimensions and gender accounting for 14.2% of shape variance.
Conclusions: Thoracic morphology undergoes significant structural and proportional transformations during early life and adolescence. Post-puberty, females exhibit a more elongated thorax with inclined ribs, while males develop a broader, more cylindrical configuration.
