# Physical Examination for Chronic Pain

## Overview

The physical examination in chronic pain medicine serves multiple purposes: confirming or refuting diagnostic hypotheses generated from the history, identifying the pain mechanism (nociceptive, neuropathic, or nociplastic), detecting red flag pathology, and establishing a functional baseline. A targeted, systematic examination -- combining general musculoskeletal assessment, focused neurological testing, and provocative maneuvers -- is essential for every pain medicine consultation.

## General Observation and Functional Assessment

### Before Formal Examination

The examination begins before you touch the patient. During the interview, observe posture, guarding, facial grimacing, movement patterns, and use of assistive devices. Note pain behaviors such as bracing, rubbing, sighing, limping, and restricted range of motion. Assess gait: an antalgic gait (shortened stance phase on the affected side) indicates weight-bearing pain, a Trendelenburg gait indicates hip abductor weakness, a spastic gait suggests myelopathy, and a steppage gait suggests foot drop from peroneal neuropathy. Sit-to-stand and stand-to-sit transitions reveal functional capacity and pain-related movement limitation that standardized testing may not capture.

### Waddell Signs (Nonorganic Physical Signs)

Waddell described five categories of nonorganic physical signs: superficial tenderness, simulation tests (axial loading and rotation), distraction tests (discrepancy between seated and supine straight leg raise), regional disturbances (non-dermatomal sensory loss, give-way weakness), and overreaction. Three or more positive categories suggest psychosocial overlay -- importantly, this does not mean malingering. These signs indicate that psychosocial factors are amplifying pain behavior and should trigger psychosocial assessment, not dismissal of the patient.

## Spinal Examination

### Cervical Spine

The cervical examination begins with range of motion assessment: flexion, extension, lateral flexion, and rotation, documented in degrees. The Spurling test applies axial compression with extension and lateral flexion toward the symptomatic side; reproduction of radicular arm pain constitutes a positive result, with a sensitivity of 50% and specificity of 86% for cervical radiculopathy. The Lhermitte sign -- an electric shock sensation down the spine or limbs with neck flexion -- suggests cervical myelopathy or demyelinating disease. The shoulder abduction sign, where placing the hand on top of the head relieves radicular pain by reducing tension on the compressed nerve root, can be a helpful confirmatory finding.

### Thoracic Spine

Thoracic spine examination includes palpation for point tenderness (which may indicate fracture or metastasis), assessment for kyphosis and scoliosis, and rib spring testing for costovertebral joint pain. Thoracic radiculopathy is rare but can be assessed with an adaptation of the slump test.

### Lumbar Spine

Lumbar range of motion is assessed in flexion (using the Schober test: mark 10 cm above and 5 cm below the posterior superior iliac spine, with normal excursion of 5 cm or more), extension, and lateral flexion. The straight leg raise (SLR) is positive when radicular pain (not hamstring tightness) is reproduced at 30-70 degrees of hip flexion; it has a sensitivity of 91% and specificity of 26% for L4-S1 radiculopathy. The crossed straight leg raise reproduces radicular pain in the affected leg when the contralateral leg is raised -- it has low sensitivity (29%) but high specificity (88%) for disc herniation, making it highly diagnostic when positive. The femoral nerve stretch test (reverse SLR), performed with the patient prone and knee flexion with hip extension reproducing anterior thigh pain, suggests L2-L4 radiculopathy. The facet loading test uses extension with ipsilateral rotation to reproduce axial back pain, suggesting facet-mediated pain, though its diagnostic accuracy is limited and the gold standard remains a diagnostic medial branch block.

<image>Sequential illustration of key lumbar spine provocative maneuvers: (A) straight leg raise test showing the examiner elevating the extended leg with radicular pain distribution marked along the L5 and S1 dermatomes, (B) crossed straight leg raise test, (C) Lasegue sign with dorsiflexion augmentation, and (D) femoral nerve stretch test in prone position with anterior thigh pain distribution highlighted, each with annotations indicating the nerve roots tested and diagnostic sensitivity/specificity values</image>

## Sacroiliac Joint Examination

No single test is diagnostic for sacroiliac joint (SIJ) dysfunction. A cluster of three or more positive provocative tests has reasonable diagnostic utility, with a sensitivity of 94% and specificity of 78%. The key provocative tests are FABER (Patrick's test), which combines flexion, abduction, and external rotation of the hip with posterior pelvic pain suggesting SIJ dysfunction; the compression test, applying lateral compression of the iliac wings; the distraction test, applying anteroposterior pressure on the anterior superior iliac spines bilaterally; the thigh thrust (posterior shear), with the hip flexed to 90 degrees and an axial load applied through the femur; and the Gaenslen test, hyperextending one hip off the edge of the table. The gold standard for SIJ diagnosis remains a fluoroscopically guided intra-articular diagnostic block, with 75% or greater pain relief considered positive.

## Hip and Extremity Examination

### Hip

The FADDIR test (flexion, adduction, internal rotation) producing anterior groin pain suggests femoroacetabular impingement or labral tear. The log roll test (passive internal and external rotation of the hip in extension) producing pain suggests intra-articular hip pathology. Differentiating hip from lumbar radiculopathy is straightforward: hip pathology produces groin pain with internal rotation, while radiculopathy produces posterior pain with the straight leg raise.

### Knee

Knee examination includes palpation of joint lines and assessment of patellofemoral crepitus, ligamentous testing (anterior and posterior drawer, Lachman, valgus and varus stress tests), and the McMurray test for meniscal pathology.

### Shoulder

Shoulder examination includes the Neer and Hawkins impingement tests, Speed and Yergason tests for biceps tendinopathy, the empty can test for supraspinatus pathology, and cross-body adduction for acromioclavicular joint involvement.

## Neurological Examination for Chronic Pain

### Motor Assessment

Strength testing follows a myotomal pattern. Strength is graded on the MRC 0-5 scale.

| Nerve Root | Key Muscle(s) | Action Tested | Reflex |
|-----------|--------------|--------------|--------|
| C5 | Deltoid, biceps | Shoulder abduction, elbow flexion | Biceps |
| C6 | Wrist extensors, brachioradialis | Wrist extension | Brachioradialis |
| C7 | Triceps, wrist flexors, finger extensors | Elbow extension, wrist flexion | Triceps |
| C8 | Finger flexors, hand intrinsics | Finger flexion, grip | — |
| T1 | Interossei | Finger abduction/adduction | — |
| L2 | Iliopsoas | Hip flexion | — |
| L3 | Quadriceps | Knee extension | Patellar |
| L4 | Tibialis anterior | Ankle dorsiflexion | Patellar |
| L5 | EHL, hip abductors | Great toe extension, hip abduction | — |
| S1 | Gastrocnemius, soleus, peroneus longus | Ankle plantarflexion | Achilles  |  Give-way weakness -- a sudden collapse during testing -- suggests pain inhibition or functional overlay rather than true neurological weakness. |

### Sensory Assessment

Sensory testing should follow a dermatomal distribution using light touch with a cotton wisp (testing A-beta fiber function), pinprick for sharp/dull discrimination (A-delta fiber function), temperature with a cold tuning fork or thermal rollers (C fiber and A-delta function), and vibration with a 128 Hz tuning fork (large fiber and dorsal column function). The examiner should map areas of hypoesthesia (reduced sensation), hyperesthesia (increased sensation), allodynia (pain from normally innocuous stimuli), and hyperalgesia (increased pain from normally painful stimuli). Non-dermatomal sensory loss patterns, such as hemisensory loss or stocking distribution stopping sharply at the knee, should prompt consideration of central pathology or psychosocial contributors.

### Reflexes

Deep tendon reflexes are tested at biceps (C5-6), brachioradialis (C5-6), triceps (C7), patellar (L3-4), and Achilles (S1-2). Hyporeflexia or areflexia indicates a lower motor neuron lesion such as radiculopathy, plexopathy, or peripheral neuropathy. Hyperreflexia with clonus indicates an upper motor neuron lesion (myelopathy) and is an urgent red flag in the setting of neck or back pain. The Babinski sign and Hoffman sign should be assessed to evaluate for myelopathy in cervical spine pathology.

<image>Comprehensive dermatome map showing anterior and posterior views of the body with color-coded dermatome distributions from C2 to S5, overlaid with myotome testing positions at key levels (C5 shoulder abduction, C7 elbow extension, L4 ankle dorsiflexion, L5 great toe extension, S1 ankle plantarflexion), and reflex testing sites marked with corresponding nerve root levels</image>

## Bedside Assessment of Neuropathic Pain

### Clinical Signs to Elicit

Several bedside tests help identify neuropathic pain mechanisms. Static mechanical allodynia is assessed by gentle pressure with a finger on the painful area. Dynamic mechanical allodynia -- the most characteristic finding of neuropathic pain with central sensitization -- is tested by light stroking with a cotton wisp or brush, and is mediated by sensitized A-beta pathways. Pinprick hyperalgesia is an exaggerated pain response to a safety pin compared to the contralateral side. Temporal summation, tested by repeated pinprick at 1-2 Hz in the same spot producing progressively increasing pain, is the clinical correlate of wind-up. Cold allodynia is assessed by applying an acetone drop or cold metal to the skin. The coexistence of sensory loss with pain is a hallmark of neuropathic pain -- finding reduced perception of pinprick, touch, temperature, or vibration in the same area where the patient reports pain strongly supports a neuropathic mechanism.

### Tinel Sign

Percussion over a nerve trunk producing tingling or an electric sensation radiating distally constitutes a positive Tinel sign. It is tested at the carpal tunnel (median nerve), cubital tunnel (ulnar nerve), tarsal tunnel (tibial nerve), or along a site of nerve injury or neuroma.

## Quantitative Sensory Testing (QST)

QST is a standardized psychophysical testing battery that measures sensory thresholds and suprathreshold responses. The DFNS (German Research Network on Neuropathic Pain) protocol includes 13 parameters: cold and warm detection thresholds, cold and heat pain thresholds, mechanical detection threshold (using von Frey filaments), mechanical pain threshold and sensitivity (using pinprick), dynamic mechanical allodynia (using a brush), wind-up ratio (temporal summation), vibration detection threshold, and pressure pain threshold (using algometry).

QST identifies sensory phenotypes that may guide treatment. A loss-of-function phenotype (predominant sensory loss) suggests deafferentation. A gain-of-function phenotype (predominant hyperalgesia and allodynia) suggests peripheral or central sensitization. Mixed phenotypes combine both. Loss-of-function and gain-of-function phenotypes may respond differently to treatments, making QST potentially useful for mechanism-based treatment selection. Its limitations include the need for a trained examiner, time-intensive administration (30-45 minutes), and dependence on patient attention and cooperation.

<image>Quantitative sensory testing setup showing a clinician performing standardized tests on a patient's forearm: von Frey filament application for mechanical detection threshold, pinprick stimulator for mechanical pain threshold, thermal probe (thermode) for warm and cold detection thresholds, tuning fork for vibration threshold, and a computer screen displaying the resulting sensory profile Z-score graph with gain-of-function and loss-of-function deviations from normative data highlighted in different colors</image>

## Vascular and Autonomic Assessment

Skin color and temperature asymmetry may suggest CRPS (acute phase: warm, red, and edematous; chronic phase: cool, blue, and atrophic) or vascular insufficiency. Edema should be quantified with circumferential measurement. Trophic changes -- hair loss, nail changes, and skin atrophy -- suggest CRPS or chronic vascular insufficiency. Sudomotor function (asymmetric sweating in CRPS) can be formally assessed with the quantitative sudomotor axon reflex test (QSART). Peripheral pulses should always be assessed to evaluate for vascular claudication mimicking neurogenic claudication.

## Clinical Pearls

A positive crossed straight leg raise (contralateral SLR) has low sensitivity but high specificity (88%) for lumbar disc herniation -- when present, it significantly increases diagnostic confidence. Dynamic mechanical allodynia (pain from light brushing) is the most characteristic clinical sign of neuropathic pain with central sensitization and indicates A-beta fiber-mediated pain through sensitized central pathways. Waddell signs indicate psychosocial distress amplifying pain behavior, not malingering -- this distinction is critical for maintaining the therapeutic relationship and directing the patient toward appropriate psychological support. Hyperreflexia, clonus, or a positive Babinski or Hoffman sign in a patient with neck or back pain is a red flag for myelopathy requiring urgent imaging and neurosurgical evaluation.

## References

1. Haanpaa M, Attal N, Backonja M, et al. NeuPSIG guidelines on neuropathic pain assessment. *Pain*. 2011;152(1):14-27.
2. Rolke R, Baron R, Maier C, et al. Quantitative sensory testing in the German Research Network on Neuropathic Pain (DFNS): standardized protocol and reference values. *Pain*. 2006;123(3):231-243.
3. Laslett M, Aprill CN, McDonald B, Young SB. Diagnosis of sacroiliac joint pain: validity of individual provocation tests and composites of tests. *Man Ther*. 2005;10(3):207-218.
4. Waddell G, McCulloch JA, Kummel E, Venner RM. Nonorganic physical signs in low-back pain. *Spine*. 1980;5(2):117-125.