The Social Security Administration (SSA) has two primary programs intended to provide for those who cannot work due to being disabled.
The first program, supplemental security income (SSI), is available for both the elderly and the disabled. SSI benefits are granted on a means-adjusted basis, meaning the greater your need, the greater your benefit.
The other program is known as Social Security Disability Insurance, or SSDI. It is intended for those who have earned a safety cushion should their work cause them to be disabled. SSDI benefits are determined by age, given the assumption that an older worker has paid more taxes, thus deserving more benefits.