How do pointe shoes support the body?
Two parts of the shoe work together to support the entire weight of the body on the platform of the shoe: the toe box and the shank.
The toe box, firm yet malleable, holds the toes together and keeps them straight. The shank is a stiffened part of the sole, usually a layer or several layers of material between the insole and the outer sole, which supports the entire foot on pointe.
Shanks are made in different degrees of strength, or stiffness, so that each dancer can choose the amount of support she needs. The dancer should never rely on an overly stiff shank. Instead, she must develop so much strength that the shoe is a partner, not a prop. Choosing the correct shank strength facilitates this development.
Read more about pointe shoe structure.