Body Functions, Structures, and Client Factors
Body functions, body structures, and client factors are the person-level capacities and characteristics that an occupational therapist considers when explaining why a person can or cannot carry out everyday occupations. Drawing on the World Health Organization's International Classification of Functioning, Disability and Health (ICF) and codified in the AOTA Occupational Therapy Practice Framework, this area groups the physiological functions of body systems, the anatomical parts that support them, and the values, beliefs, and spirituality that a client brings to participation.
Definition
Body functions are the physiological functions of body systems (including psychological functions); body structures are the anatomical parts such as organs and limbs; and client factors, in occupational therapy usage, comprise these together with the values, beliefs, and spirituality that reside within the person and influence engagement in occupation.
Scope
This area orients the reader to the underlying capacities that support occupational performance rather than to occupations themselves. It collects four topic clusters used in occupational therapy reasoning: motor control and movement, sensory processing and integration, cognitive functions, and emotional and psychological functions. Each is treated as a reference topic that connects basic neuroscience and physiology to participation in daily life. Specific assessment protocols and intervention dosing are out of scope.
Sub-topics
Core questions
- Which body functions and structures support, or limit, a person's participation in valued occupations?
- How do impairments in motor, sensory, cognitive, and emotional functions translate into activity limitations?
- How do values, beliefs, and spirituality as client factors shape what a person chooses to do?
- How can the ICF and the OTPF vocabularies be used to describe person-level capacities consistently?
Key concepts
- Body functions
- Body structures
- Client factors (values, beliefs, spirituality)
- International Classification of Functioning, Disability and Health (ICF)
- Impairment versus activity limitation versus participation restriction
- Person-Environment-Occupation interaction
Mechanisms
Occupational therapy frameworks treat body functions and structures as the substrate of performance: motor, sensory, cognitive, and affective systems combine to enable the actions that make up an occupation. The ICF model links this person level to activity and participation, so that an impairment in a body function may or may not produce an activity limitation depending on the demands of the task and the supports in the environment. Client factors that are not strictly physiological, such as values and spirituality, are placed at the same person level because they also shape engagement.
Clinical relevance
This area provides the shared vocabulary clinicians use to describe the capacities that underlie occupational performance and to communicate with rehabilitation teams across disciplines. It is an organising reference for relating basic body-system science to participation in daily life and does not prescribe assessment choices or interventions for any individual.
Evidence & guidelines
The conceptual structure of this area follows two foundational documents: the World Health Organization's International Classification of Functioning, Disability and Health, which defines body functions, body structures, activities, and participation, and the AOTA Occupational Therapy Practice Framework (Fourth Edition), which adapts these constructs and adds client factors as a domain element. Both are consensus reference documents rather than empirical studies.
History
The separation of person-level capacities from the activities they support matured with the World Health Organization's 2001 ICF, which replaced a purely impairment-based view with a biopsychosocial model linking body functions and structures to activity and participation. Occupational therapy incorporated this language into successive editions of its Practice Framework, the fourth of which formalised body functions, body structures, and values/beliefs/spirituality together as client factors.
Related topics
Seminal works
- who-icf-2001
- aota-otpf4-2020
Frequently asked questions
- What is the difference between body functions and client factors in occupational therapy?
- Body functions and body structures are the physiological functions and anatomical parts of body systems. In the Occupational Therapy Practice Framework, client factors is the broader domain element that includes body functions and structures together with the person's values, beliefs, and spirituality.
- Why does this area sit between basic science and occupational performance?
- Because the ICF model treats body functions and structures as the substrate that enables activity and participation; impairments here help explain occupational performance problems but do not, by themselves, determine them, since task demands and environment also matter.