Interpreting Examination Findings — Interpret examination findings in relation to anatomy and physiology of the involved body system(s). - National Physical Therapy Examination NPTE

SECTION 1

Historical Context & Motivation

The ability to interpret examination findings within the context of anatomy and physiology has been the cornerstone of clinical reasoning in physical therapy since the profession's inception. Early practitioners relied heavily on observable movement patterns and palpation, but the evolution of clinical science demanded a more systematic approach to linking signs and symptoms with specific body structures and physiological processes. The NPTE tests this competency because accurate interpretation of examination data is foundational to differential diagnosis, prognosis, and effective plan of care development. Without a robust understanding of how clinical findings map onto anatomical and physiological frameworks, therapists risk misidentifying the source of impairment and pursuing ineffective or even harmful interventions.

1920s • Emergence of Physical Rehabilitation

Post-World War I demand for rehabilitation specialists led to the formalization of physical therapy education, with anatomy and kinesiology as foundational coursework. Early clinicians relied on observation and manual muscle testing to correlate findings with nerve and muscle anatomy.

1950s • Polio Epidemic and Manual Muscle Testing

The polio epidemic demanded precise grading of muscle weakness. Clinicians like Daniels and Worthingham systematized manual muscle testing, linking specific weakness patterns to spinal cord segment and peripheral nerve involvement—a direct application of interpreting findings through anatomy.

1984 • APTA Guide to Physical Therapist Practice

The American Physical Therapy Association published practice frameworks emphasizing a systems-based examination model, requiring clinicians to integrate findings from musculoskeletal, neuromuscular, cardiovascular-pulmonary, and integumentary systems.

2001 • ICF Framework Adoption

The World Health Organization's International Classification of Functioning, Disability and Health (ICF) was adopted, encouraging therapists to interpret body structure and function findings in context of activity limitations and participation restrictions.

2024 • Current NPTE Content Outline

The Federation of State Boards of Physical Therapy (FSBPT) content outline explicitly requires candidates to interpret examination findings in relation to anatomy and physiology across all body systems, reflecting the centrality of this skill in modern clinical practice.

The critical question this lesson addresses is: when a patient presents with a specific constellation of examination findings—such as diminished reflexes, altered sensation, or abnormal gait patterns—how does the clinician systematically trace those findings back to the anatomy and physiology of the involved body system to arrive at an accurate clinical interpretation? Mastering this process is essential for NPTE success and for safe, effective patient care.

SECTION 2

Core Principles of Interpretation

Interpreting examination findings requires a structured clinical reasoning process that bridges the gap between raw data—such as range of motion measurements, muscle grades, reflex responses, and vital signs—and the anatomical and physiological substrates that explain those data. The physical therapist must possess not only factual anatomical knowledge but also the ability to reason from observed signs to probable tissue involvement, physiological dysfunction, and pathological processes. The following core principles guide this interpretive framework and represent the conceptual foundation tested on the NPTE.

Anatomical Correlation

Every clinical finding should be mapped to a specific anatomical structure or region. For example, weakness in wrist extension with intact shoulder abduction points to the radial nerve (C6–C7) rather than the upper trunk of the brachial plexus.

Physiological Reasoning

Findings must be interpreted through the lens of normal physiology. Elevated resting heart rate combined with orthostatic hypotension suggests compromised autonomic regulation of cardiovascular function, not simply deconditioning.

Pattern Recognition

Clusters of findings form recognizable patterns. A capsular pattern of restricted motion at the glenohumeral joint (external rotation > abduction > internal rotation) indicates joint capsule involvement rather than isolated muscular tightness.

Systems Integration

Pathology in one body system often produces findings across multiple systems. A patient with congestive heart failure may present with lower extremity edema (integumentary), decreased exercise tolerance (cardiovascular), and distal muscle weakness (musculoskeletal).

Differential Interpretation

The clinician must consider competing explanations for findings and use additional tests to narrow possibilities. A positive straight leg raise may indicate lumbar disc herniation, piriformis syndrome, or hamstring pathology—anatomical knowledge guides differentiation.

✦

KEY TAKEAWAY

Think of the examination like reading a topographic map: individual findings are elevation points, but it is the pattern formed by connecting those points that reveals the underlying terrain—the anatomy and physiology creating those clinical features. A single finding (one elevation point) is ambiguous; clusters of findings mapped to known anatomical and physiological frameworks reveal the clinical landscape with precision.

SECTION 3

Visual Framework — Dermatome and Myotome Mapping

One of the most clinically powerful applications of interpreting examination findings through anatomy involves the dermatome-myotome-reflex triad. When a patient presents with radiculopathy, the therapist evaluates sensory distribution (dermatome), motor strength (myotome), and deep tendon reflexes to localize the involved spinal nerve root. The following diagram illustrates how findings from these three examination domains converge to identify the level of involvement in the upper and lower extremities.

This chart maps key upper and lower extremity nerve root levels to their corresponding dermatome distributions, myotome actions, and deep tendon reflexes. When all three columns align for a given nerve root, the clinician has high confidence in localizing the level of radiculopathy.

Consider a patient presenting with numbness over the lateral forearm and thumb, weakness of wrist extension graded 3/5, and a diminished brachioradialis reflex. The diagram above shows that all three findings converge at the C6 nerve root level. This anatomical correlation enables the therapist to interpret these examination findings as consistent with C6 radiculopathy, differentiating it from peripheral nerve entrapment, which would produce a different pattern of sensory and motor deficits. The triad approach—dermatome, myotome, reflex—exemplifies how systematic anatomical reasoning transforms isolated clinical data points into a coherent diagnostic picture.

SECTION 4

Physiological Mechanisms Behind Common Findings

Understanding why a specific finding occurs requires knowledge of normal physiology and how pathological processes alter it. This section examines the physiological mechanisms underlying four major categories of examination findings frequently tested on the NPTE: neuromuscular, musculoskeletal, cardiovascular-pulmonary, and integumentary. Each category illustrates how anatomical knowledge and physiological reasoning interact to yield clinical interpretation.

Neuromuscular Findings: Upper vs. Lower Motor Neuron Lesions

The distinction between upper motor neuron (UMN) and lower motor neuron (LMN) lesions is fundamental to neurological examination interpretation. The physiological basis lies in the organization of the motor pathway: the UMN (corticospinal tract) normally exerts inhibitory modulation on spinal reflex arcs. When this descending inhibition is lost (UMN lesion), the reflex arc becomes hyperexcitable, producing hyperreflexia, spasticity, and a positive Babinski sign. Conversely, when the LMN itself is damaged, the reflex arc is interrupted at its efferent limb, resulting in hyporeflexia, flaccidity, fasciculations, and muscle atrophy. This physiological framework allows the therapist to interpret reflex and tone findings and immediately determine whether the lesion resides above or below the anterior horn cell.

Cardiovascular-Pulmonary Findings: Hemodynamic Responses

Vital sign monitoring during physical therapy reveals critical information about cardiovascular and pulmonary physiology. A normal exercise heart rate response follows a linear increase with increasing workload, governed by sympathetic nervous system activation and withdrawal of parasympathetic tone. An exaggerated heart rate response (excessive rise relative to workload) may indicate deconditioning, anemia, or autonomic dysfunction. A blunted heart rate response in a patient on beta-blockers reflects the pharmacological blockade of β₁-adrenergic receptors in the sinoatrial node, meaning the therapist must use the Rate of Perceived Exertion (RPE) scale rather than heart rate to gauge exercise intensity.

Musculoskeletal Findings: End-Feel and Tissue Involvement

When assessing passive range of motion, the therapist evaluates end-feel—the quality of resistance felt at the end of the available range. A firm end-feel (capsular stretch) is normal for hip internal rotation and reflects the viscoelastic properties of the joint capsule and ligaments. A hard end-feel (bone-on-bone) is normal for elbow extension, where the olecranon contacts the olecranon fossa. An empty end-feel—where the patient stops movement due to severe pain before any mechanical resistance is reached—is always pathological and may indicate acute inflammation, fracture, or neoplasm. By understanding the anatomical structures creating each type of end-feel, the therapist can determine which tissue is limiting motion.

💡

Clinical Pearl

A pathological end-feel is one that occurs at the wrong joint, the wrong motion, or at the wrong point in the range. For example, a hard end-feel during knee flexion (which should normally be soft tissue approximation) suggests a loose body or osteophyte—anatomy that should not be creating bony contact at that joint in that direction.

SECTION 5

Systems-Based Classification of Findings

The NPTE requires candidates to interpret findings across all four practice pattern categories defined by the Guide to Physical Therapist Practice. The following diagram provides a systems-based classification framework showing common examination findings organized by body system, the anatomical structures involved, and the physiological mechanisms that produce those findings. This systematic approach is essential for differential interpretation, especially when findings from multiple systems overlap.

The four-system framework organizes common examination findings by body system, linking each finding to its anatomical basis and the physiological mechanism responsible. The examination tools listed at the bottom of each panel represent the primary assessment methods used to generate those findings.

Examination Finding	Anatomical Structure	Physiological Mechanism	Clinical Interpretation
Positive Trendelenburg sign	Gluteus medius; superior gluteal nerve (L4–S1)	Inability to stabilize pelvis due to abductor insufficiency	Hip abductor weakness or L5 nerve root involvement
Positive Phalen's test	Median nerve within carpal tunnel	Wrist flexion compresses nerve → ischemia → paresthesia	Carpal tunnel syndrome (median nerve entrapment)
Crackles (rales) on auscultation	Alveoli and small airways	Fluid in alveoli disrupts gas exchange and creates popping sounds on inspiration	Pulmonary edema, pneumonia, or atelectasis
Absent dorsalis pedis pulse	Dorsalis pedis artery (branch of anterior tibial artery)	Arterial occlusion reduces distal perfusion	Peripheral arterial disease; assess ABI and skin integrity

Selected examination findings with anatomical and physiological interpretation

SECTION 6

Worked Example — Interpreting a Patient Case

The following worked example demonstrates the systematic process of interpreting examination findings in relation to anatomy and physiology, as expected on the NPTE. The case involves a 58-year-old patient who presents with progressive right lower extremity symptoms following an insidious onset of low back pain.

Case: Progressive Right Lower Extremity Weakness with Low Back Pain

1
Step 1 — Gather and Organize Examination Findings

The patient presents with the following findings: pain radiating from the low back into the posterior thigh and lateral leg to the dorsum of the foot; numbness over the lateral leg and first dorsal web space; weakness of ankle dorsiflexion (3+/5) and great toe extension (3/5); intact patellar reflex (2+); diminished medial hamstring reflex (1+); positive straight leg raise at 35° on the right reproducing concordant symptoms; and antalgic gait with foot drop. Organize these into sensory, motor, reflex, and functional categories.

Organized findings: Sensory (lateral leg, dorsal foot); Motor (ankle DF, great toe ext); Reflex (medial hamstring ↓); Functional (foot drop gait)
2
Step 2 — Map Findings to Anatomical Structures

The sensory distribution over the lateral leg and first dorsal web space corresponds to the L5 dermatome. Weakness of ankle dorsiflexion implicates the tibialis anterior (innervated by the deep peroneal nerve, primarily L4–L5 myotome), and great toe extension implicates the extensor hallucis longus (L5 myotome). The diminished medial hamstring reflex is associated with the L5 nerve root. All findings converge on the L5 nerve root level.

Anatomical correlation: L5 nerve root — dermatome, myotome, and reflex all converge
3
Step 3 — Apply Physiological Reasoning

The L5 nerve root exits between the L4 and L5 vertebral bodies (though it is most commonly compressed by the L4–L5 disc). Disc herniation produces mechanical compression and chemical irritation (phospholipase A₂ and inflammatory cytokines) of the nerve root, leading to demyelination and axonal injury. This explains the combined sensory loss (damaged sensory axons), motor weakness (damaged motor axons), and reflex diminution (impaired afferent-efferent conduction through the reflex arc). The positive straight leg raise at 35° (below 70°) increases the tension on the sciatic nerve and its L5 root component, reproducing concordant symptoms—a highly sensitive finding for lumbar disc herniation.

Physiological mechanism: Disc herniation → nerve root compression → demyelination/axonal damage → combined sensory-motor-reflex deficit
4
Step 4 — Differential Interpretation

Could this presentation be due to a peroneal nerve injury rather than an L5 radiculopathy? A common peroneal nerve lesion would also produce ankle dorsiflexion weakness and numbness of the dorsal foot, but it would spare hip abduction (gluteus medius, also L5) and the medial hamstring reflex. The involvement of the reflex and the concordant pain pattern radiating from the lumbar spine confirms this is a radiculopathy, not a peripheral entrapment. Additionally, the positive SLR specifically implicates neural tension from a proximal lesion. Intact patellar reflex (L3–L4) helps rule out a more proximal lesion at L4.

Clinical interpretation: Right L5 radiculopathy, likely secondary to L4–L5 disc herniation
5
Step 5 — Integrate into Clinical Decision-Making

The interpretation of these findings as L5 radiculopathy guides the plan of care: directional preference exercises (McKenzie approach) to centralize symptoms, neural mobilization techniques, progressive strengthening of the L5-innervated musculature, and gait training with an ankle-foot orthosis as needed to prevent falls due to foot drop. The 3/5 strength grade and sensory deficit indicate moderate nerve involvement, and the therapist should monitor for progression of weakness or development of bowel/bladder changes (cauda equina syndrome) that would warrant urgent referral.

Interpretation drives intervention: directional preference, neural mobilization, AFO consideration, red flag monitoring

SECTION 7

Comparing Interpretation Across Body Systems

Different body systems require different interpretive strategies, and NPTE questions frequently test the candidate's ability to distinguish between findings that appear similar but arise from different anatomical and physiological origins. Understanding these distinctions is critical because the choice of intervention depends entirely on accurate system-level attribution of the finding.

Finding	Musculoskeletal Interpretation	Neuromuscular Interpretation	Cardiovascular/Pulmonary Interpretation
Lower extremity weakness	Disuse atrophy, post-surgical inhibition (e.g., quad lag after TKA). Pattern follows specific muscle or group.	Nerve root, peripheral nerve, or central lesion. Pattern follows myotome or nerve distribution.	Peripheral arterial disease causing claudication-induced weakness. Worsens with activity, improves with rest.
Gait deviation	Antalgic (pain avoidance), joint stiffness, leg length discrepancy.	Spastic (scissors), ataxic (wide-based), steppage (foot drop), Parkinsonian (shuffling, festinating).	Dyspnea-limited gait distance; intermittent claudication pattern.
Pain with movement	Reproduced by specific joint or muscle loading. Localized to the tissue. Aggravated by mechanical stress.	Radiating, burning, or electric. Follows nerve distribution. May increase with neural tension tests.	Chest pain or pressure with exertion (angina). Calf pain with walking (claudication). Eases with rest.
Edema	Localized to injured joint. Associated with effusion, warmth. Trauma or overuse history.	Complex regional pain syndrome (CRPS): disproportionate edema with allodynia. Sympathetic nervous system involvement.	Bilateral, dependent. Pitting edema with CHF. Unilateral with DVT (medical emergency).

The same clinical finding can have dramatically different interpretations depending on the body system involved.

✦

KEY TAKEAWAY

Think of examination findings as symptoms displayed on a car's dashboard warning lights: a single warning light (e.g., 'check engine') could indicate dozens of different problems. The skilled mechanic—like the skilled physical therapist—does not simply respond to the light itself but uses a diagnostic algorithm to determine which system is generating the signal. In clinical practice, the combination of patient history, systems review, and targeted tests and measures acts as that algorithm, allowing the therapist to attribute findings to the correct anatomical and physiological source.

SECTION 8

Connection to Advanced Clinical Reasoning

While the NPTE primarily tests the ability to interpret findings in relation to anatomy and physiology at a foundational clinical level, the same reasoning framework scales to advanced diagnostic challenges in clinical practice. Understanding how basic interpretation connects to more sophisticated clinical reasoning models prepares you not only for the examination but also for the complexities of patient care beyond licensure.

Foundational Interpretation (NPTE Level)	Advanced Clinical Reasoning (Post-Licensure)
Map a single finding to one anatomical structure (e.g., positive Neer's impingement → supraspinatus tendon)	Integrate multiple findings with imaging, lab values, and patient comorbidities to assess tissue-specific contributions in complex, multi-pathology patients
Identify UMN vs. LMN signs and localize the lesion level	Apply neuroanatomical reasoning to differentiate between cortical, subcortical, brainstem, and spinal lesion locations using cranial nerve and long tract sign combinations
Interpret vital sign abnormalities during exercise in relation to cardiovascular physiology	Analyze exercise stress test data in patients with complex cardiac histories, accounting for pharmacological effects, ventricular remodeling, and autonomic neuropathy
Recognize capsular vs. non-capsular patterns at a joint	Differentiate intra-articular from extra-articular pathology using selective tissue tension principles, diagnostic ultrasound correlation, and response to trial interventions
Classify wounds by depth and tissue involvement	Integrate wound findings with vascular assessment (ABI), nutritional labs (albumin, prealbumin), HbA1c, and tissue oxygenation data to predict healing potential

Foundational NPTE-level interpretation naturally extends into advanced practice reasoning.

The advanced reasoning framework emphasizes the concept of hypothesis-oriented clinical reasoning, where the therapist generates multiple competing hypotheses based on initial findings and then systematically tests each hypothesis through additional examination procedures. This approach is an extension of the foundational anatomy-physiology interpretation framework: instead of a single finding-to-structure mapping, the clinician manages multiple simultaneous mappings and evaluates their relative probability based on the weight of evidence. Mastering the foundational level tested on the NPTE creates the cognitive scaffolding necessary for this more complex reasoning.

SECTION 9

Practice Problems

Question 1: CONCEPTUAL

A patient presents with hyperreflexia in the lower extremities, a positive Babinski sign bilaterally, and spastic gait. Is this consistent with an upper motor neuron (UMN) or lower motor neuron (LMN) lesion? Explain the physiological basis for your answer.

Show answer

This presentation is consistent with an upper motor neuron lesion. The corticospinal tract (UMN pathway) normally exerts inhibitory modulation over spinal reflex arcs. When this descending inhibition is lost—as occurs with a lesion above the level of the anterior horn cell (e.g., in the spinal cord, brainstem, or cortex)—the spinal reflexes become hyperexcitable, producing hyperreflexia and spasticity. The positive Babinski sign (great toe extension with fanning of the lateral toes) results from disinhibition of the flexor withdrawal reflex, a primitive reflex normally suppressed by the intact corticospinal tract in adults. An LMN lesion would instead produce hyporeflexia, flaccidity, and muscle atrophy because the reflex arc itself is interrupted at the efferent limb.

Question 2: BASIC

A patient reports numbness over the medial leg and medial foot, demonstrates 3/5 knee extension strength, and has a diminished patellar reflex. Which nerve root level is most likely involved? Identify the key anatomical structures at that level.

Show answer

The findings converge on the L4 nerve root. The L4 dermatome covers the medial leg and medial foot. The key myotome action at L4 is knee extension, performed by the quadriceps femoris muscle group (rectus femoris, vastus lateralis, vastus medialis, vastus intermedius), which is innervated by the femoral nerve (L2–L4). The patellar reflex tests the L3–L4 reflex arc, involving the femoral nerve as both the afferent and efferent limb and the anterior horn cells at L3–L4 spinal cord levels. The L4 nerve root exits the spinal canal between the L4 and L5 vertebral bodies and may be compressed by an L3–L4 disc herniation or L4–L5 lateral recess stenosis.

Question 3: INTERMEDIATE

A 72-year-old patient with type 2 diabetes presents with a non-healing wound on the plantar surface of the right foot over the first metatarsal head. Examination reveals absent dorsalis pedis and posterior tibial pulses, diminished sensation to monofilament testing in a stocking distribution, and an ankle-brachial index (ABI) of 0.6. Interpret these findings in relation to the anatomy and physiology of the involved body systems.

Show answer

This presentation involves dysfunction across multiple body systems. The absent pedal pulses and ABI of 0.6 (normal is 1.0–1.3; values below 0.9 indicate peripheral arterial disease) reflect atherosclerotic narrowing of the lower extremity arteries (likely the anterior tibial and posterior tibial arteries), a macrovascular complication of diabetes that reduces tissue perfusion and impairs wound healing. The stocking-distribution sensory loss indicates diabetic peripheral neuropathy, a length-dependent axonal degeneration caused by chronic hyperglycemia damaging the vasa nervorum (microvascular supply to peripheral nerves) and producing direct metabolic injury to axons. The distal-to-proximal gradient reflects the vulnerability of the longest axons. The non-healing plantar wound results from the convergence of these two pathologies: neuropathy eliminates protective sensation (the patient does not perceive tissue damage from pressure), and arterial insufficiency denies the wound the oxygen and nutrients needed for the inflammatory and proliferative phases of healing.

Question 4: APPLIED

During an exercise session, a 55-year-old patient post-CABG on metoprolol demonstrates the following findings: resting heart rate of 62 bpm, blood pressure of 118/74 mmHg, heart rate after 5 minutes of moderate-intensity treadmill walking of 74 bpm, and RPE of 14 ('somewhat hard'). The target heart rate zone calculated using the Karvonen formula (60–80% HRR) is 120–142 bpm. Should the therapist rely on the heart rate zone or the RPE to guide exercise intensity? Explain the physiological basis for your answer.

Show answer

The therapist should rely on RPE rather than the calculated heart rate zone. Metoprolol is a selective β₁-adrenergic receptor antagonist (beta-blocker) that blocks the effect of catecholamines on the sinoatrial node and myocardium. Physiologically, during exercise, the sympathetic nervous system increases heart rate by stimulating β₁ receptors in the SA node. Beta-blockers competitively inhibit this receptor, producing a blunted chronotropic (heart rate) response to exercise. This means the patient's heart rate will not reach the target zone calculated using standard Karvonen parameters (which assume a normal chronotropic response). The RPE of 14 ('somewhat hard') falls within the appropriate range for moderate-intensity exercise (12–14 on the Borg 6–20 scale) and provides a more accurate reflection of the patient's actual physiological effort than the suppressed heart rate. The Karvonen formula would need to be recalculated using a beta-blocker-adjusted maximum heart rate, but RPE remains the more reliable and practical guide in this scenario.

Question 5: CRITICAL THINKING

A 45-year-old patient presents with bilateral lower extremity weakness that is worse distally than proximally, absent deep tendon reflexes throughout, and decreased sensation in a glove-and-stocking pattern. Symptoms have progressed over the past two weeks following a respiratory infection. The patient also reports difficulty taking deep breaths. Interpret these findings across the involved body systems, identify the most likely condition, and explain why the respiratory complaint is the most clinically urgent finding.

Show answer

This presentation is classic for Guillain-Barré Syndrome (GBS), an acute inflammatory demyelinating polyradiculoneuropathy. Anatomically, GBS involves autoimmune-mediated destruction of peripheral nerve myelin sheaths (and sometimes axons), often triggered by molecular mimicry following a preceding infection. The ascending, distal-to-proximal pattern of weakness reflects the length-dependent vulnerability of peripheral nerves—the longest axons are affected first. The areflexia (absent DTRs) confirms peripheral nerve involvement (LMN pattern), as the afferent and efferent limbs of the reflex arc pass through demyelinated segments. The glove-and-stocking sensory loss reflects involvement of sensory axons in the same length-dependent pattern. The respiratory complaint is the most clinically urgent finding because it indicates that the ascending demyelination is reaching the phrenic nerve (C3–C5) and intercostal nerves (T1–T12), which innervate the diaphragm and intercostal muscles respectively. Compromise of these nerves leads to respiratory failure, which is the leading cause of mortality in GBS. This patient requires immediate monitoring of forced vital capacity (FVC); if FVC drops below 20 mL/kg, intubation and mechanical ventilation may be required. The physical therapist must recognize this finding as a medical emergency warranting immediate physician notification, even though the musculoskeletal and neuromuscular findings are the presenting complaints.

SUMMARY

Summary — Interpreting Examination Findings

Summary

Interpreting examination findings in relation to anatomy and physiology is the central clinical reasoning skill tested on the NPTE. The process begins with anatomical correlation—mapping each finding (sensory changes, motor weakness, reflex abnormalities, vital sign changes, wound characteristics) to a specific structure or pathway. It deepens through physiological reasoning, explaining why a finding occurs based on normal and pathological physiology—such as understanding that hyperreflexia results from loss of UMN inhibition while hyporeflexia results from disruption of the LMN reflex arc. The dermatome-myotome-reflex triad is a powerful tool for localizing spinal nerve root involvement, and the four-system framework (musculoskeletal, neuromuscular, cardiovascular-pulmonary, integumentary) ensures comprehensive interpretation.

Critical to NPTE success is recognizing that the same finding—such as lower extremity weakness, gait deviation, or edema—can have fundamentally different interpretations depending on the body system involved. The clinician uses pattern recognition and differential interpretation to attribute findings to the correct anatomical and physiological source, which in turn drives intervention selection. Always remember: findings from multiple systems often coexist in the same patient, and the skilled therapist integrates across systems to construct the most complete and accurate clinical picture.