Final answer:
Stability about the lateral axis is provided by the center of gravity and the width of the base of support. A person remains stable as long the center of gravity remains above this base. Widening the base and lowering the center of gravity improve stability, which is controlled by the central nervous system.
Step-by-step explanation:
What provides stability around or about the lateral axis is largely dependent on the center of gravity (cg) and the base of support. Humans achieve stability in this axis by having their center of gravity above the hip joints, which act as pivotal points, and between their narrowly-separated feet. As with a pencil balanced on its eraser, a person can maintain stable equilibrium with respect to sideways displacements as long as the cg remains above the base of support. Instability occurs when displacements cause the cg to extend beyond this area.
To enhance stability, widening the base of support by spacing the feet apart is particularly effective. Furthermore, lowering the center of gravity — for instance, by bending at the knees as football players do — also contributes to increased stability. Devices like canes, crutches, or walkers can significantly improve stability as they expand the base of support even more. For systems in stable equilibrium, such as a person or a pencil, the challenge is to control displacement quickly enough to prevent the cg from moving outside the base of support, which is a function of the central nervous system developed from infancy. Women typically have a lower center of gravity than men, and young children have it positioned between their shoulders, affecting their stability.