Definitions of the terms elderly and geriatrics are somewhat vague. Indeed, the distinction between younger and older adults is difficult to make on a biological basis. Functional and social needs of older patients also play a role in the definitions of elderly and geriatrics, but are difficult to quantify. From a practical standpoint, patients in the geriatric population may be considered to be elderly, and the commonest definition of the term elderly is about 75 years of age. However, this working definition may vary from 65 to 85 years of age.