The Occupational Therapy Practice Framework (OTPF) describes the domains and processes inherent to the profession of occupational therapy (OT). According to the OTPF, the term client factors refers to those components that influence actions or occupations.¹ For example, a child’s neuromuscular status is considered a client factor. Client factors include both body structures and functions (Table 11-1). The term body structures refers to the parts that make up the human body. For example, the structure of the hand includes bones, muscles, tendons, nerves, and blood vessels. A child with a missing thumb would have a deficient body structure that may interfere with his occupational performance. The term body functions refers to how the body part, organ, or organ system works. In the former example, body function would include the child’s hand strength or coordination. Deficits in body functions may also result in poor occupational performance. Since body functions and body structures are essential to understanding occupational performance, this chapter provides an overview of the structures in each body system. Lastly, the author provides an overview of how body structures and body functions influence occupational performance.

TABLE 11-1

Client Factors

CLIENT FACTORS
CATEGORY AND DEFINITION	EXAMPLES
Values: Principles, standards, or qualities considered worthwhile or desirable by the client who holds them.	Honesty with self and with others Personal religious convictions Commitment to family.
Beliefs: Cognitive content held as true.	He or she is powerless to influence others Hard work pays off.
Spirituality: The “personal quest for understanding answers to ultimate questions about life, about meaning, and the sacred” (Moyers & Dale, 2007, p. 28).	Daily search for purpose and meaning in one’s life Guiding actions from a sense of value beyond the personal acquisition of wealth or fame.
BODY FUNCTIONS
Categories
Mental Functions (affective, cognitive, perceptual)
Specific Mental Functions Higher-level cognitive Attention Memory Perception Thought Mental functions of sequencing complex movement Emotional Experience of self and time	Judgment, insight Awareness, sustained, selective, attention Short-term, long-term, and working memory Discrimination, spatial, and temporal relationships Recognition, categorization, generalization, Execution of learned movement patterns Coping, adapting Body image, self-concept, self-esteem
Global Mental Functions
Consciousness Orientation Temperament and personality Energy and drive Sleep (physiological process)	Level of arousal, level of consciousness Orientation to person, place, time, self, and others Emotional stability Motivation, impulse control, and appetite
Sensory Functions and Pain
Seeing and related functions Hearing functions Vestibular functions Taste functions Smell functions Proprioceptive functions Touch functions Pain Temperature and pressure	Detection/registration, modulation, and integration of sensations from the body and environment Visual awareness Sensation of securely moving against gravity Association of taste & smell Awareness of body position and space Comfort with the feeling of being touched by others Localizing pain Thermal awareness
Neuromusculoskeletal and Movement-related Functions
Functions of joints and bones Joint mobility Joint stability Muscle power Muscle tone Muscle endurance Motor reflexes Involuntary movement reactions Control of voluntary movement Gait patterns	ROM Postural alignment Strength Degree of muscle tone (e.g., flaccidity, spasticity, fluctuating) Endurance Righting and supporting Eye–hand/foot coordination, bilateral integration, Walking patterns and impairments
Cardiovascular, Hematologic, Immunologic, and Respiratory System Function Cardiovascular system function Hematological and immunological system function Respiratory system function
	Blood pressure functions (hypertension, hypotension, postural hypotension), and heart rate Rate, rhythm, and depth of respiration Physical endurance, aerobic capacity, stamina, and fatigability
Voice and Speech Functions • Voice functions • Fluency and rhythm • Alternative vocalization functions
Digestive, Metabolic, and Endocrine System Function • Digestive system function • Metabolic system and endocrine system function
Genitourinary and Reproductive Functions • Urinary functions • Genital and reproductive functions
Skin and Related-structure Functions
• Skin functions • Hair and nail functions	Protective functions of the skin–presence or absence of wounds, cuts, or abrasions Repair function of the skin–wound healing
BODY STRUCTURES
Categories
Structure of the nervous system Eyes, ear, and related structures Structures involved in voice and speech Structures of the cardiovascular, immunologic, and respiratory systems Structures related to the digestive, metabolic, and endocrine systems Structure related to the genitourinary and reproductive systems Structures related to movement Skin and related structures

Moyers, P. A., & Dale, L. M. (2007). The guide to occupationaltherapy practice (2nd ed.). Bethesda, MD: AOTA Press.

Note. Some data adapted from the ICF (WHO, 2001).

World Health Organization. (2001). International classification of functioning, disability, and health (ICF).Geneva: Author.

*Adapted from Table 2 from: American Occupational Therapy Association: Occupational therapy practice framework: Domain and process, 2nd edition, Am J Occup Ther 62(6):625–703, 2008.

Successful engagement in daily occupations is dependent upon the interactions of many client factors including one’s values, beliefs, and spirituality. However, the focus of this chapter is on the client factors related to body structures and functions.

Anatomy is the branch of biology that studies the structures of the human body. Physiology is the branch of biology that studies the functions of the structures of the human body. The human body comprises living matter. A unifying concept in biology is that structure or shape determines function in all living matter. One’s successful engagement in chosen daily occupations may be impaired if specific client factors related to body structures and functions are impaired or abnormal.

The organization of the human body is hierarchical. Atoms are the smallest unit of matter. By definition, matter is anything that takes up space and has mass or weight. Atoms of different elements have unique masses and space requirements. The most abundant elements found in living matter are carbon, hydrogen, oxygen, nitrogen, and phosphorus. Atoms link together (bond) to form molecules. For example, two hydrogen atoms bond with one oxygen atom to form one molecule of water (H₂O). Molecules come together to form cells. Cells are the smallest units of living matter. The cells found in the human body are eukaryotic cells. Eukaryotic cells have a membrane bound nucleus that contains a person’s genetic information, for example, deoxyribonucleic acid (DNA) and genes. Cells come together to form tissues. There are four basic types of tissue found in the human body. The four tissue types are epithelial, connective, muscle, and nervous (Table 11-2). Tissues come together to form organs. Organs, for example, the heart, are made of two or more types of tissues. Organs come together to form organ systems, for example, the cardiovascular system, or the circulatory system, which consists of the heart and associated vessels. Organ systems come together to form organisms. The human body has numerous organ systems that work together to allow one’s active participation in chosen daily occupations.

TABLE 11-2

Major Tissues of the Body

TISSUE TYPE	STRUCTURE	FUNCTION	EXAMPLES IN THE BODY
Epithelial	One or more layers of densely arranged cells with very little extracellular matrix May form either sheets or glands	Covers and protects the body surface Lines body cavities Movement of substances (absorption, secretion, excretion) Glandular activity	Outer layer of skin Lining of the respiratory, digestive, urinary, reproductive tracts Glands of the body
Connective	Sparsely arranged cells surrounded by a large proportion of extracellular matrix often containing structural fibers (and sometimes mineral crystals)	Supports body structures Transports substances throughout the body	Bones Joint cartilage Tendons and ligaments Blood Fat
Muscle	Long fiberlike cells, sometimes branched, capable of pulling loads; extracellular fibers sometimes hold muscle fiber together	Produces body movements Produces movements of organs such as the stomach, heart Produces heat	Heart muscle Muscles of the head/neck, arms, legs, trunk Muscles in the walls of hollow organs such as the stomach, intestines
Nervous	Mixture of many cell types, including several types of neurons (conducting cells) and neuroglia (support cells)	Communication between body parts Integration/regulation of body functions	Tissue of brain and spinal cord Nerves of the body Sensory organs of the body