The Skeleton Sets the Base. Muscle Changes the Contour.
Glute appearance is influenced by pelvic anatomy, muscle mass, fat distribution and the shape of the surrounding legs and torso.
The gluteus maximus contributes most of the visible mass and rearward projection of the glutes. The gluteus medius contributes to upper and lateral hip contour while also playing an important role in hip stability.
Hamstring and thigh development also affects how the lower body flows visually from the hips into the legs.