A stiffened panel including at least one stiffener, known as a longitudinal stiffener, extending substantially from one extremity of the panel to another and whose trace on a surface of the panel follows a path having non-zero geodesic curvature between the two extremities of the stiffener. This configuration makes it possible to optimize both a stiffness of the panel and its resistance to the force flow to which the panel is subjected to during operation by minimizing its mass through an optimum definition of an orientation of the stiffeners relative to the force flow.