Final answer:
Males generally have a wider/larger ribcage and shoulders compared to females, especially after the adolescent growth spurt that results in a broader chest and shoulders for males and wider hips and pelvis for females. This sexual dimorphism in human anatomy is defined by the differences in the thoracic cage and pectoral girdle.
Step-by-step explanation:
The ribcage and shoulders of males are generally wider/larger than females. During adolescence, males experience greater growth in muscles and bones, particularly in the upper body. This growth pattern results in males having broader shoulders and chests relative to their hips. Conversely, females tend to develop a wider pelvis and hips in relation to their shoulders and chest, contributing to differences in body composition and shape. The pectoral girdle, consisting of the paired clavicles and scapulas, forms the shoulders and attaches the arms to the trunk.
In adults, the differences in the thoracic cage or ribcage, a structure comprising the ribs, sternum, thoracic vertebrae, and costal cartilages, further accentuate these dimorphic characteristics. The thoracic cage functions to protect vital organs, support the shoulder girdles, and enable breathing. These anatomical features contribute to the sexual dimorphism observed in adult human body composition.