8.1 Cervical Spine Disorders, Whiplash & Cervical Radiculopathy

8.1 Cervical Spine Disorders, Whiplash & Cervical Radiculopathy

[!NOTE] DHA Clinical Competency Focus: Cervical spine disorders represent one of the highest-yield musculoskeletal domains on the DHA Physiotherapist licensing examination. Candidates are expected to master upper versus lower cervical arthrokinematics, execute and interpret Wainner's diagnostic cluster for cervical radiculopathy, safely calculate mechanical traction dosages, implement pressure biofeedback protocols for deep neck flexor retraining, stage whiplash injuries via the Quebec Task Force criteria, differentiate cervicogenic headaches using the Flexion-Rotation Test, and immediately recognize upper motor neuron red flags indicative of cervical spondylotic myelopathy.

The human cervical spine is engineered to balance high multi-planar mobility with neural protection for the spinal cord, vertebral arteries, and exiting nerve roots. Clinical evaluation of cervical disorders demands a systematic understanding of segmental arthrokinematics, specialized neurodynamic provocative testing, and rigid screening for sinister neurocompressive pathology.

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1. Functional Anatomy & Biomechanics of the Cervical Spine

The cervical spine is divided anatomically and functionally into the upper (craniovertebral) cervical complex (C0–C2) and the subaxial cervical spine (C3–C7). Each region displays distinct joint morphology, ligamentous restraints, and kinematic coupling patterns.

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|                         Cervical Spine Biomechanical Division                     |
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| Craniovertebral Region (C0-C2):                                                   |
|   - Atlanto-Occipital (O-A / C0-C1): Flexion / Extension (~15-20° total)          |
|   - Atlanto-Axial (A-A / C1-C2): Axial Rotation (~35-40° per side, 50% total)     |
|   - Key Ligaments: Transverse ligament of atlas, paired alar ligaments           |
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| Subaxial Cervical Spine (C3-C7):                                                  |
|   - Facet Orientation: 45° between frontal and transverse planes                  |
|   - Motion: Combined flexion, extension, side-bending, and rotation               |
|   - Uncovertebral Joints (Luschka): Medial border of intervertebral foramen (IVF) |
|   - Coupling: Ipsilateral side-bending and axial rotation                         |
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The Upper Craniovertebral Complex (C0–C2)

• Atlanto-Occipital Joint (O-A / C0–C1):

  • Articular Geometry: Formed by the articulation of the two convex occipital condyles with the two concave superior articular facets of the atlas (C1). This represents a classic convex-on-concave arthrokinematic interface.
  • Primary Kinematics: Predominantly sagittal plane motion ("nodding" or "yes" joint). Flexion produces an anterior roll of the occipital condyles with a posterior glide; extension produces a posterior roll with an anterior glide. Total sagittal range of motion (ROM) is approximately 15° to 20°.
  • Lateral Flexion & Rotation: Extremely limited (~3–5° of lateral flexion), accompanied by paradoxical contra-lateral rotation (e.g., right side-bending produces left conjunct axial rotation).

• Atlanto-Axial Joint (A-A / C1–C2):

  • Articular Geometry: A complex of three distinct articulations: the median pivot (trochoid) joint between the odontoid process (dens) of C2 and the anterior arch/transverse ligament of C1, plus bilateral lateral facet joints. Crucially, the lateral articular facets of both C1 and C2 are biconvex (covered by thick dome-shaped articular cartilage), allowing the atlas to "telescope" or screw down during axial rotation.
  • Primary Kinematics: The primary rotational engine of the neck ("no" joint). Mediates 50% of total cervical rotation, contributing 35° to 40° of axial rotation to each side before any subaxial rotation is recruited.
  • Critical Ligamentous Restraints:
    • Transverse Ligament of the Atlas: Part of the cruciform ligament, spanning horizontally between the medial tubercles of the C1 lateral masses behind the dens. It prevents anterior translation / subluxation of C1 on C2 during cervical flexion, maintaining the atlantodental interval (ADI) within safe limits (<3 mm in adults, <4.5–5 mm in children). Pathological laxity occurs in rheumatoid arthritis, Down syndrome, and odontoid trauma.
    • Alar Ligaments: Paired cords extending from the posterosuperior aspect of the dens obliquely superolaterally to the medial margins of the occipital condyles. They primary check contralateral axial rotation and contralateral lateral flexion (e.g., the left alar ligament tightens during right cervical rotation).

The Subaxial Cervical Spine (C3–C7)

• Facet Joint (Zygapophyseal) Architecture:

  • The subaxial facet joints are oriented at approximately 45° to the transverse plane (slanted halfway between the horizontal and frontal planes). The superior articular facets face superiorly, posteriorly, and medially, while the inferior facets face inferiorly, anteriorly, and laterally.
  • Kinematics: During flexion, the inferior facets of the superior vertebra glide anterosuperiorly (opening the facet joints and expanding intervertebral foramina by ~20–30%). During extension, they glide posteroinferiorly (closing the facet joints and narrowing foramina).

• Kinematic Coupling Rules:

  • In the subaxial spine (C3–C7), lateral flexion and axial rotation are coupled to the same (ipsilateral) side throughout the entire physiological ROM. Right side-bending is mandatory coupled with right axial rotation.
  • In the upper cervical spine (C0–C2), coupling occurs to the opposite (contralateral) side to maintain forward horizontal gaze.

• Uncovertebral Joints (Joints of Luschka):

  • Arise between the uncinate processes on the posterolateral margins of the superior vertebral endplates (C3–C7) and the beveled inferior surfaces of the vertebra above.
  • These pseudo-joints develop between ages 6 and 9 as secondary fissures in the intervertebral disc. They provide lateral structural stability, prevent posterior and lateral disc extrusion, and guide sagittal flexion-extension.
  • Clinical Significance: Hypertrophic osteophytes arising from uncovertebral arthrosis (uncarthrosis) project directly into the anteromedial aspect of the intervertebral foramen, representing the primary anatomical mechanism of foraminal stenosis in older individuals.

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2. Cervical Radiculopathy: Pathomechanics, Segmental Profiles & Wainner's Cluster

Cervical radiculopathy is a pathological process involving mechanical compression or biochemical inflammation of a cervical spinal nerve root, presenting with dermatomal sensory changes, myotomal weakness, and diminished deep tendon reflexes (DTRs).

Pathomechanisms: Herniation vs. Spondylosis

1. Soft Disc Herniation (Posterolateral Bulge / Extrusion):
   • Predominates in younger patients (<45 years).
   • Acute mechanical impingement combined with neurochemical irritation from phospholipase A2 and inflammatory cytokines released by the nucleus pulposus.
2. Cervical Spondylosis / Foraminal Spondylotic Encroachment:
   • Accounts for over 70% of radiculopathy cases, predominating in patients >50 years.
   • Chronic osteophytic spurring from uncovertebral joints anteromedially and zygapophyseal facet joints posterolaterally, coupled with degenerative disc space collapse.
   • Note on Cervical Nerve Root Exit: The cervical nerve roots exit above their numerically corresponding vertebral body (e.g., the C5 nerve root exits at the C4–C5 intervertebral foramen; the C6 root exits at C5–C6; the C7 root exits at C6–C7; the C8 nerve root exits between C7 and T1).

Segmental Neurological Profiles

Wainner's Diagnostic Clinical Prediction Rule (CPR)

Wainner et al. (2003) established an internationally validated cluster of four clinical physical examination tests that dramatically improves the diagnostic accuracy for cervical radiculopathy.

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|              Wainner's Diagnostic Cluster for Cervical Radiculopathy               |
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| 1. Spurling's Test A (Neck Compression):                                          |
|    - Cervical extension, ipsilateral lateral flexion, axial downward overpressure |
|    - Positive: Reproduction of radiating arm pain / paresthesia into dermatome    |
|    - High Specificity (92-93%), Low-to-Moderate Sensitivity (~50%)                |
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| 2. Upper Limb Tension Test 1 (ULTT-1 / Elvey / Median Nerve Bias):                |
|    - Sequential shoulder depression, 110° abduction, wrist/finger extension,      |
|      forearm supination, elbow extension, contralateral cervical side-bending     |
|    - Positive: Symptom reproduction, structural differentiation, >10° ROM deficit |
|    - Highest Sensitivity (97%) -> PRIMARY EXCLUSION (RULE-OUT) TEST               |
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| 3. Cervical Distraction Test:                                                     |
|    - Patient supine, therapist applies ~14 kg (30 lbs) axial manual traction      |
|    - Positive: Complete relief or marked reduction of radicular upper arm symptoms|
|    - High Specificity (90%), Moderate Sensitivity (44%)                           |
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| 4. Ipsilateral Cervical Rotation < 60°:                                           |
|    - Active cervical rotation to the symptomatic side measures less than 60°     |
|    - Positive: Objective rotation restriction secondary to foraminal narrowing   |
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Diagnostic Likelihood Ratios of Wainner's Cluster

• 2 of 4 Positive Tests: Sensitivity 0.60, Specificity 0.72, Positive Likelihood Ratio (+LR) = 1.7–2.1.
• 3 of 4 Positive Tests: Specificity increases to 94%, +LR = 6.1.
• All 4 of 4 Positive Tests: Specificity reaches 99%, +LR = 30.3 (virtually pathognomonic for cervical radiculopathy).
• DHA Key Takeaway: A negative ULTT-1 essentially rules OUT cervical radiculopathy due to its exceptional sensitivity (0.97, -LR = 0.12).

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3. Conservative Rehabilitation Protocols: Traction, Neurodynamics & Deep Neck Flexor Retraining

Conservative physical therapy is the first-line intervention for cervical radiculopathy, successfully resolving over 75–85% of cases without surgical decompression.

Mechanical Cervical Traction Parameters

Mechanical traction decompresses neural foramina, separates vertebral bodies, tensions the posterior longitudinal ligament, and decreases intradiscal pressure.

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|                   Clinical Dosage: Mechanical Cervical Traction                  |
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| Patient Position:  Supine with head supported in occipital halter harness        |
| Angle of Pull:     24° to 30° flexion (opens C5-C7 lower cervical foramina)       |
|                    0° to 15° neutral (focuses pull on C1-C4 upper cervical)      |
| Traction Force:    Initial session: 10 to 15 lbs (4.5 to 7.0 kg)                 |
|                    Progressive therapeutic: 20 to 30 lbs (~10% total body weight)|
| Cycle Mode:        Intermittent (e.g., 60 sec hold / 20 sec rest; 30s on / 10s off|
| Total Duration:    15 to 20 minutes per treatment session                        |
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• Precautions & Absolute Contraindications: Acute cervical trauma without imaging, severe osteoporosis, rheumatoid arthritis / Down syndrome (alar/transverse ligament laxity), cervical myelopathy, vascular insufficiency (vertebral artery disease), carotid bruits, and unmanaged severe hypertension.

Neurodynamic Mobilization: Sliders vs. Tensioners

Neurodynamic techniques manage neural mechano-sensitivity and restore neural bed excursion:

• Neural Sliders (Gliders):
  • Involve movement of two or more joints where elongation at one site is simultaneously compensated by slackening at an adjacent site (e.g., performing wrist extension with ipsilateral cervical side-bending, followed by wrist flexion with contralateral cervical side-bending).
  • Clinical Indication: Acute, highly irritable radiculopathy. Sliders produce substantial longitudinal nerve excursion with minimal strain or intraneural pressure increase, facilitating evacuation of intraneural edema and restoring axoplasmic flow.
• Neural Tensioners:
  • Involve concurrent elongation at both ends of the neural pathway (e.g., extending the wrist while side-bending the cervical spine to the contralateral side).
  • Clinical Indication: Subacute and chronic, low-irritability conditions. Tensioners restore viscoelastic compliance and mechanical tolerance to tensile loading.

Deep Neck Flexor (DNF) Motor Control Training

The deep neck flexor muscles (longus colli and longus capitis) provide essential cervical lordosis support and segmental stabilization. In patients with neck pain and radiculopathy, these deep postural stabilizers undergo reflexive inhibition and fatty infiltration, replaced by excessive, fatigue-prone activity in superficial muscles (sternocleidomastoid [SCM] and anterior scalenes).

  [ Baseline Calibration: 20 mmHg ]
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  [ Stage 1: Target 22 mmHg (Hold 10s x 10 reps) ]
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  [ Stage 2: Target 24 mmHg (Hold 10s x 10 reps) ]
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  [ Stage 3: Target 26 mmHg (Hold 10s x 10 reps) ]
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  [ Stage 4: Target 28 mmHg (Hold 10s x 10 reps) ]
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  [ Stage 5: Target 30 mmHg (Hold 10s x 10 reps) ]

Cranio-Cervical Flexion Test (CCFT) Protocol

1. Instrument: Pressure Biofeedback Unit (PBU / Chattanooga Stabilizer).
2. Setup: Patient lies supine hook-lying with the uninflated air bladder positioned suboccipitally beneath the cervical lordosis. The bladder is inflated to a standardized baseline pressure of 20 mmHg.
3. Execution: The patient is instructed to perform a slow, gentle head-nodding action ("craniocervical flexion" as if nodding "yes") to flatten the lordosis and incrementally elevate the pressure across five 2-mmHg stages: 22, 24, 26, 28, and 30 mmHg.
4. Performance Criteria: The patient must hold the target pressure steadily for 10 seconds, repeating for 10 cycles, without engaging in substitution strategies.
5. Substitution Traps: Palpable superficial SCM or anterior scalene contraction, jaw clenching / teeth grinding, breath holding, or head lifting (cervical retraction/retraction shear instead of pure craniocervical sagittal rotation).

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4. Whiplash-Associated Disorders (WAD) & Headache Differentials

Whiplash describes an acceleration-deceleration mechanism of energy transfer to the neck, typically resulting from rear-end or lateral motor vehicle collisions.

Quebec Task Force (QTF) WAD Classification

Evidence-Based Whiplash Management Rules

• The Cervical Collar Rule: Routine or prolonged use of a cervical collar (soft or rigid) is strongly discouraged. Collar immobilization promotes kinesiophobia, soft-tissue adaptive shortening, proprioceptive loss, and muscular atrophy. Active pain-free movement within the first 72 hours produces significantly superior long-term functional outcomes.
• Prognostic Indicators: High initial pain (>5.5/10), high Neck Disability Index (NDI >30%), cold hyperalgesia (indicative of central sensitization), and high post-traumatic stress symptoms predict poor long-term recovery.

Headache Differentials: Cervicogenic Headache vs. Migraine vs. Tension-Type

Cervicogenic headache (CGH) arises from referred pain mediated by the trigeminocervical nucleus caudalis, where sensory afferents from the upper three cervical nerves (C1, C2, C3) converge with the spinal tract of the trigeminal nerve (CN V, particularly V1/V2).

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|                         Headache Differential Diagnostic Table                    |
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| Parameter        | Cervicogenic (CGH)     | Migraine              | Tension-Type (TTH)    |
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| Laterality       | Strictly Unilateral    | Often Unilateral      | Bilateral             |
| Pain Quality     | Dull, aching, non-     | Throbbing, pulsating, | Non-throbbing, dull,  |
|                  | throbbing              | moderate-to-severe    | band-like, tight      |
| Starting Point   | Suboccipital / neck,   | Frontotemporal /      | Diffuse, band around  |
|                  | radiates to front/eye  | ocular                | whole cranium         |
| Provocation      | Neck movement, awkward | Stress, foods, bright | Mental stress, fatigue|
|                  | sustained postures     | lights, hormonal shifts|                      |
| Autonomic Signs  | Rare; mild lacrimation | Nausea, vomiting,     | Absent                |
|                  | possible               | photophobia, phonophobia|                     |
| Physical Testing | Positive FRT (<32°);   | Normal cervical tests;| Cervical pericranial  |
|                  | C1-C3 segment hypomobile| routine neuro normal  | tenderness, normal FRT|
+------------------+------------------------+-----------------------+-----------------------+

The Flexion-Rotation Test (FRT)

• Purpose: The most validated manual assessment tool to detect C1–C2 (atlanto-axial) joint dysfunction in cervicogenic headache (sensitivity 90%, specificity 90%).
• Technique: The patient lies relaxed in supine. The examiner fully flexes the cervical spine to the end of range (which effectively "locks out" the subaxial C3–C7 segments due to anatomical facet tension). Maintaining full end-range flexion, the examiner gently rotates the head passively to the left and right, recording the ROM.
• Diagnostic Cutoff: Normal physiological C1–C2 rotation in full flexion is 44° to 45° per side. A test is positive if there is an absolute rotation of less than 32° or a side-to-side restriction asymmetry of ≥10°, with reproduction of familiar headache symptoms.

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5. Cervical Spondylotic Myelopathy (CSM) Red Flags & Post-Operative Management

Cervical Spondylotic Myelopathy (CSM) is the most common cause of spinal cord dysfunction in adults over age 55, resulting from chronic progressive cord compression.

Clinical Red Flags & Pathophysiology

• Etiology: Congenital canal stenosis (<13 mm AP canal diameter), posterior osteophyte bars, ossification of the posterior longitudinal ligament (OPLL), or hypertrophied/buckled ligamentum flavum.
• Upper Motor Neuron (UMN) Features: Unlike radiculopathy (which exhibits lower motor neuron hyporeflexia and flaccidity), CSM exhibits hyperreflexia, spasticity, non-dermatomal sensory loss, and pathological reflexes.

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|                Cook's Diagnostic Cluster for Cervical Myelopathy                  |
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| 1. Gait Deviation: Ataxic, wide-based, clumsy, unsteady tandem gait               |
| 2. Positive Hoffman's Sign: Flicking distal phalanx of middle finger produces     |
|    involuntary flexion/adduction of the thumb and index finger                    |
| 3. Inverted Brachioradialis Reflex: Tapping radial styloid produces paradoxical  |
|    finger flexion with diminished or absent elbow flexion                         |
| 4. Positive Babinski Sign: Stroking lateral plantar foot produces great toe       |
|    extension (dorsiflexion) and fanning of toes                                   |
| 5. Age > 45 Years                                                                 |
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| Diagnostic Yield:                                                                 |
|   - 3 of 5 positive: Specificity = 94%, +LR = 5.3                                 |
|   - 4 of 5 positive: Specificity = 99%, +LR = 30.9                                |
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• Additional Signs: Lhermitte's sign (sudden electric-shock sensation shooting down the spine into the limbs upon neck flexion), Myelopathy Hand / Finger Escape Sign (inability to maintain adduction and extension of the 4th and 5th digits for 30 seconds).
• Mandatory Action: Immediate cessation of manual therapy. High-velocity low-amplitude (HVLA) thrust manipulation is strictly contraindicated. The patient requires urgent neurosurgical referral for magnetic resonance imaging (MRI) and decompression.

Post-Operative Cervical Care

• Anterior Cervical Discectomy and Fusion (ACDF) vs. Cervical Disc Replacement (CDR / Arthroplasty):
  • ACDF: Removal of disc and osteophytes with insertion of bone graft/cage and anterior plate fixation. Early mobility is strictly limited to protect fusion.
  • CDR: Implantation of a motion-preserving artificial disc prosthesis; avoids adjacent segment pathology, allowing earlier controlled mobilization.
• Post-Operative Precautions (Phase I, Weeks 0–6):
  • Lifting Restriction: No lifting objects heavier than 5 to 10 lbs (equivalent to a gallon of milk).
  • Spinal Motion Restrictions: Strictly avoid cervical extension, aggressive rotation, and active overhead lifting.
  • Collar Weaning: Wear rigid (Miami J / Aspen) or soft collar as prescribed by the operating surgeon, weaning gradually by weeks 4–6.
  • Red Flag Post-Op Complications: Progressive dysphagia (difficulty swallowing), dysphonia / hoarseness (recurrent laryngeal nerve neuropraxia), stridor / dyspnea (retropharyngeal hematoma—emergency!), wound dehiscence.
  • Rehabilitation Focus: Walking for cardiovascular fitness, gentle active-assisted ROM within pain-free arc (avoiding end-range extension), scapular retractor setting, and gentle sub-maximal isometric cervical stabilizing without shear.

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6. Clinical Scenario & DHA Exam Traps

Clinical Scenario: Differentiating Neck and Arm Symptoms

Scenario: A 52-year-old female presents to an outpatient physical therapy clinic in Dubai complaining of a sharp, burning ache radiating from the right side of her neck down the lateral forearm into the thumb and index finger, accompanied by pins and needles. On examination:

• Active cervical rotation to the right is restricted to 42° with sharp arm pain reproduction; rotation to the left is 68°.
• Spurling's Test A to the right recreates tingling into her thumb.
• Manual cervical distraction in supine relieves her arm symptoms completely.
• ULTT-1 (median nerve bias) on the right side reproduces radicular pain at 85° elbow extension, which intensifies with contralateral neck side-bending.
• Deep tendon reflexes: Right brachioradialis 1+, right biceps 1+, right triceps 2+; left upper limb reflexes are all 2+.
• Myotomal testing shows 4/5 strength in right wrist extension (ECRL/ECRB) and elbow flexion (biceps); triceps and finger flexors are 5/5.
• Pathological reflexes (Hoffman, Babinski) are absent, and gait is unremarkable.

Clinical Assessment & Diagnosis: The presentation represents textbook right C6 cervical radiculopathy. All 4 items of Wainner's cluster are positive (Spurling A, Distraction, ULTT-1, and ipsilateral rotation <60°), providing a diagnostic specificity of 99% (+LR = 30.3). Motor deficits in wrist extension and elbow flexion, paired with hypoesthesia of the thumb/index finger and a depressed brachioradialis reflex, precisely isolate the C6 root.

DHA Exam Traps to Avoid

[!WARNING]

• Trap 1: Confusing Diagnostic Test Roles in Wainner's Cluster: DHA exam questions often ask which test is best to rule out versus rule in radiculopathy. ULTT-1 has an exceptional sensitivity of 97%; therefore, a negative ULTT-1 effectively rules out cervical radiculopathy (-LR = 0.12). Conversely, Spurling's A and Distraction have high specificities (~90–93%) and are used to rule in the diagnosis.
• Trap 2: Collar Use in Whiplash (WAD): When asked about the optimal management for WAD Grade I–II, never select prolonged collar immobilization or bed rest. Modern evidence mandates early active movement, postural re-education, and exercise. Prescribing a rigid cervical collar beyond 48–72 hours is an automatic incorrect answer.
• Trap 3: Spondylotic Myelopathy vs. Cervical Radiculopathy: Do not confuse radiculopathy with myelopathy. If a clinical vignette describes hyperactive patellar/Achilles reflexes, clonus, wide-based ataxic gait, or bilateral clumsy hands in an older adult with neck stiffness, the diagnosis is cervical myelopathy (UMN), NOT radiculopathy (LMN). Cervical traction and HVLA manipulation are contraindicated; the patient must be referred immediately to a spine surgeon.