import { HighYieldBox, ExamCheatSheet, Tabs, Tab, ComparisonTable, VivaScenario, ContentSection, SpecialTestCard , MedicalImage} from '@/components/content' # Lower Limb Neurological Examination Lower limb neurological examination is essential for evaluating lumbar spine pathology. Examiners expect systematic testing of key myotomes (L2-S1), dermatomes, reflexes, and identification of red flags for cauda equina syndrome. Always include gait assessment. ## Quick Reference One-Pager ## Systematic Approach **Components:** 1. **Gait**: Essential first step 2. **Motor**: Tone, power, bulk 3. **Sensory**: Light touch, pinprick 4. **Reflexes**: Knee jerk, ankle jerk, Babinski 5. **Straight leg raise**: Nerve root tension **Key Principle:** The lower limb examination must include cauda equina screening in any patient with lumbar symptoms. ## Gait Assessment **Normal Gait Phases:** - Heel strike → Stance → Toe-off → Swing **Abnormal Patterns:** **Foot Drop Gait (L5/Peroneal):** - High-stepping gait - Slapping foot on ground - Cannot heel walk **Trendelenburg Gait (L5/Hip Abductors):** - Pelvis drops on swing side - Trunk lurches to stance side **Antalgic Gait:** - Short stance phase on painful side - Non-neurological but important **Spastic Gait (UMN):** - Stiff, circumduction - Scissors gait ## Motor Examination **Look For:** - Muscle wasting (compare sides) - Fasciculations - Trophic changes - Foot drop posture **Key Areas:** - Quadriceps bulk (L3-4) - Tibialis anterior (L4-5) - Calf muscles (S1-2) - Small muscles of foot ### Myotomal Testing **Key Root Level Tests:** - **L4**: Ankle dorsiflexion + knee jerk - **L5**: EHL extension (big toe up) + NO reliable reflex - **S1**: Ankle plantarflexion + ankle jerk **Common Disc Levels:** - L4-5 disc → L5 root compression - L5-S1 disc → S1 root compression ## Sensory Examination **Key Testing Points:** - **L2**: Anterior thigh (mid-thigh) - **L3**: Medial knee - **L4**: Medial calf/malleolus - **L5**: First web space (dorsum) - **S1**: Lateral foot/little toe **Testing Technique:** - Light touch first - Pinprick if abnormality suspected - Work from abnormal to normal area - Compare sides systematically **Critical for Cauda Equina:** - Perianal region - Posterior thigh - Genitalia **Testing:** - "Is the feeling in your bottom area normal?" - Pinprick perianal if concern - Document anal tone if indicated **Red Flag:** Reduced perianal sensation = suspected cauda equina until proven otherwise. ## Reflexes **When Reflex Appears Absent:** - Patient interlocks fingers and pulls apart - Or clenches teeth - Repeat reflex testing during maneuver **Interpretation:** - Present with reinforcement = diminished but present - Absent even with reinforcement = truly absent ## Nerve Root Tension Signs ## Cauda Equina Screening **Cauda Equina Red Flags - MUST ASK:** 1. **Bladder dysfunction**: Retention, incontinence, reduced awareness 2. **Bowel dysfunction**: Incontinence, constipation 3. **Saddle anesthesia**: Numbness around perineum 4. **Sexual dysfunction**: Impotence, reduced sensation 5. **Bilateral leg symptoms**: Weakness or numbness both legs 6. **Progressive weakness**: Getting worse rapidly **If ANY present: URGENT MRI and surgical assessment** **Sensory:** - Test perianal sensation (S2-4) - Compare both sides - Test genital sensation if appropriate **Motor:** - Anal tone (digital rectal exam if indicated) - Bilateral lower limb power **Reflexes:** - Bulbocavernosus reflex - Anal wink **Post-void Residual:** - Bladder scan if retention suspected - Greater than 200mL concerning ## Pattern Recognition **L4 Radiculopathy:** - **Motor**: Weak ankle dorsiflexion, knee extension - **Sensory**: Medial calf/malleolus - **Reflex**: Reduced knee jerk **Common Cause:** L3-4 disc herniation **L5 Radiculopathy:** - **Motor**: Weak EHL (big toe extension), ankle dorsiflexion, hip abduction - **Sensory**: First web space, dorsum of foot - **Reflex**: None specific (hamstring may be reduced) **Common Cause:** L4-5 disc herniation (most common level) **S1 Radiculopathy:** - **Motor**: Weak plantarflexion, eversion, difficulty on single heel raise - **Sensory**: Lateral foot, sole, little toe - **Reflex**: Reduced ankle jerk **Common Cause:** L5-S1 disc herniation ## Upper vs Lower Motor Neuron ## Summary Presentation ## Examination Sequence 1. **Gait**: Walking, heel walking, toe walking 2. **Standing**: Romberg, single leg stance 3. **Supine inspection**: Wasting, fasciculations 4. **Tone**: Hip, knee, ankle bilaterally 5. **Power**: L2-S1 myotomes bilaterally 6. **Sensation**: L2-S1 dermatomes, saddle area 7. **Reflexes**: Knee jerk, ankle jerk, Babinski 8. **SLR**: Both legs, note angle and symptoms 9. **Femoral stretch**: If upper lumbar suspected 10. **Cauda equina screen**: Ask about bladder/bowel/saddle ## Examiner Tips