Disability is an umbrella term, covering impairments, activity limitations and participation restrictions. Impairments are problems in body functions or structures while activity limitations are difficulties encountered by an individual in executing tasks or actions. Problems experienced by an individual in life situations are called participation restrictions.

In other words, disability is not just one health problem. It is a complex phenomenon, reflecting the interaction between features of a person’s body and features of the society in which he or she lives.